Merge branch 'master' into BAEL-16646-2

testing-modules/README.md

@@ -0,0 +1,3 @@
+## Testing Modules
+
+This is an aggregator module containing multiple modules focused on testing libraries.

testing-modules/assertion-libraries/README.md

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+
+## Relevant Articles
+
+- [AssertJ’s Java 8 Features](http://www.baeldung.com/assertJ-java-8-features)
+- [AssertJ for Guava](http://www.baeldung.com/assertJ-for-guava)
+- [Introduction to AssertJ](http://www.baeldung.com/introduction-to-assertj)
+- [Testing with Google Truth](http://www.baeldung.com/google-truth)
+- [Testing with JGoTesting](http://www.baeldung.com/jgotesting)
+- [Guide to JSpec](http://www.baeldung.com/jspec)
+- [Custom Assertions with AssertJ](http://www.baeldung.com/assertj-custom-assertion)
+- [Using Conditions with AssertJ Assertions](http://www.baeldung.com/assertj-conditions)
+- [AssertJ Exception Assertions](http://www.baeldung.com/assertj-exception-assertion)
+

testing-modules/assertion-libraries/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>assertion-libraries</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>assertion-libraries</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>testing-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.truth</groupId>
+            <artifactId>truth</artifactId>
+            <version>${truth.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.truth.extensions</groupId>
+            <artifactId>truth-java8-extension</artifactId>
+            <version>${truth.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-guava</artifactId>
+            <version>${assertj-guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.javalite</groupId>
+            <artifactId>javalite-common</artifactId>
+            <version>${javalite.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jgotesting</groupId>
+            <artifactId>jgotesting</artifactId>
+            <version>${jgotesting.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.assertj</groupId>
+                <artifactId>assertj-assertions-generator-maven-plugin</artifactId>
+                <version>${assertj-generator.version}</version>
+                <configuration>
+                    <classes>
+                        <param>com.baeldung.testing.assertj.custom.Person</param>
+                    </classes>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <truth.version>0.32</truth.version>
+        <assertj-guava.version>3.1.0</assertj-guava.version>
+        <assertj-core.version>3.9.0</assertj-core.version>
+        <assertj-generator.version>2.1.0</assertj-generator.version>
+        <javalite.version>1.4.13</javalite.version>
+        <jgotesting.version>0.12</jgotesting.version>
+    </properties>
+
+</project>

testing-modules/assertion-libraries/src/main/java/com/baeldung/assertj/Dog.java

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+package com.baeldung.assertj;
+
+public class Dog {
+    private String name;
+    private Float weight;
+
+    public Dog(String name, Float weight) {
+        this.name = name;
+        this.weight = weight;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Float getWeight() {
+        return weight;
+    }
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/assertj/Member.java

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+package com.baeldung.assertj;
+
+public class Member {
+    private String name;
+    private int age;
+
+    public Member(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/assertj/Person.java

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+package com.baeldung.assertj;
+
+public class Person {
+    private String name;
+    private Integer age;
+
+    public Person(String name, Integer age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/assertj/custom/Person.java

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+package com.baeldung.assertj.custom;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Person {
+    private String fullName;
+    private int age;
+    private List<String> nicknames;
+
+    public Person(String fullName, int age) {
+        this.fullName = fullName;
+        this.age = age;
+        this.nicknames = new ArrayList<>();
+    }
+
+    public void addNickname(String nickname) {
+        nicknames.add(nickname);
+    }
+
+    public String getFullName() {
+        return fullName;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public List<String> getNicknames() {
+        return nicknames;
+    }
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/jspec/Animal.java

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+package com.baeldung.jspec;
+
+public abstract class Animal {
+
+    protected String name;
+
+    public Animal(String name) {
+        this.name = name;
+    }
+    
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Animal other = (Animal) obj;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        return true;
+    }
+    
+    
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/jspec/Cage.java

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+package com.baeldung.jspec;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+public class Cage {
+    
+    private Set<Animal> animals = new HashSet<>();
+    
+    public void put(Animal animal) {
+        animals.add(animal);
+    }
+    
+    public void put(Animal... animals) {
+        this.animals.addAll(Arrays.asList(animals));
+    }
+    
+    public Animal release(Animal animal) {
+        return animals.remove(animal) ? animal : null;
+    }
+    
+    public void open() {
+        animals.clear();
+    }
+    
+    public boolean hasAnimals() {
+        return animals.size() > 0;
+    }
+    
+    public boolean isEmpty() {
+        return animals.isEmpty();
+    }
+    
+    public Set<Animal> getAnimals() {
+        return this.animals;
+    }
+    
+    public int size() {
+        return animals.size();
+    }
+
+    @Override
+    public String toString() {
+        return "Cage [animals=" + animals + "]";
+    }
+    
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/jspec/Cat.java

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+package com.baeldung.jspec;
+
+public class Cat extends Animal {
+
+    public Cat(String name) {
+        super(name);
+    }
+
+    @Override
+    public String toString() {
+        return "Cat [name=" + name + "]";
+    }
+    
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/jspec/Dog.java

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+package com.baeldung.jspec;
+
+public class Dog extends Animal {
+
+    public Dog(String name) {
+        super(name);
+    }
+
+    @Override
+    public String toString() {
+        return "Dog [name=" + name + "]";
+    }
+    
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/truth/User.java

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+package com.baeldung.truth;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+public class User implements Comparable<User> {
+    private String name = "John Doe";
+    private List<String> emails = Arrays.asList("contact@baeldung.com", "staff@baeldung.com");
+
+    public User() {
+    }
+
+    public User(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public List<String> getEmails() {
+        return emails;
+    }
+
+    public void setEmails(List<String> emails) {
+        this.emails = emails;
+    }
+
+    @Override
+    public int hashCode() {
+        int hash = 5;
+        hash = 37 * hash + Objects.hashCode(this.name);
+        return hash;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+
+        final User other = (User) obj;
+        return Objects.equals(this.name, other.name);
+    }
+
+    @Override
+    public int compareTo(User o) {
+        return this.getName()
+            .compareToIgnoreCase(o.getName());
+    }
+
+}

testing-modules/assertion-libraries/src/main/java/com/baeldung/truth/UserSubject.java

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+package com.baeldung.truth;
+
+import com.google.common.truth.ComparableSubject;
+import com.google.common.truth.FailureStrategy;
+import com.google.common.truth.IterableSubject;
+import com.google.common.truth.SubjectFactory;
+import com.google.common.truth.Truth;
+
+public class UserSubject extends ComparableSubject<UserSubject, User> {
+
+    private UserSubject(FailureStrategy failureStrategy, User target) {
+        super(failureStrategy, target);
+    }
+
+    private static final SubjectFactory<UserSubject, User> USER_SUBJECT_FACTORY = new SubjectFactory<UserSubject, User>() {
+        @Override
+        public UserSubject getSubject(FailureStrategy failureStrategy, User target) {
+            return new UserSubject(failureStrategy, target);
+        }
+    };
+
+    public static UserSubject assertThat(User user) {
+        return Truth.assertAbout(USER_SUBJECT_FACTORY)
+            .that(user);
+    }
+
+    // Our API begins here
+    public void hasName(String name) {
+        if (!actual().getName()
+            .equals(name)) {
+            fail("has name", name);
+        }
+    }
+
+    public void hasNameIgnoringCase(String name) {
+        if (!actual().getName()
+            .equalsIgnoreCase(name)) {
+            fail("has name ignoring case", name);
+        }
+    }
+
+    public IterableSubject emails() {
+        return Truth.assertThat(actual().getEmails());
+    }
+
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/AssertJConditionUnitTest.java

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+package com.baeldung.assertj;
+
+import static org.assertj.core.api.Assertions.allOf;
+import static org.assertj.core.api.Assertions.anyOf;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.not;
+import static org.junit.Assert.fail;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.assertj.core.api.Condition;
+import org.junit.Test;
+
+public class AssertJConditionUnitTest {
+    private Condition<Member> senior = new Condition<>(m -> m.getAge() >= 60, "senior");
+    private Condition<Member> nameJohn = new Condition<>(m -> m.getName().equalsIgnoreCase("John"), "name John");
+
+    @Test
+    public void whenUsingMemberAgeCondition_thenCorrect() {
+        Member member = new Member("John", 65);
+        assertThat(member).is(senior);
+
+        try {
+            assertThat(member).isNot(senior);
+            fail();
+        } catch (AssertionError e) {
+            assertThat(e).hasMessageContaining("not to be <senior>");
+        }
+    }
+
+    @Test
+    public void whenUsingMemberNameCondition_thenCorrect() {
+        Member member = new Member("Jane", 60);
+        assertThat(member).doesNotHave(nameJohn);
+
+        try {
+            assertThat(member).has(nameJohn);
+            fail();
+        } catch (AssertionError e) {
+            assertThat(e).hasMessageContaining("<name John>");
+        }
+    }
+
+    @Test
+    public void whenCollectionConditionsAreSatisfied_thenCorrect() {
+        List<Member> members = new ArrayList<>();
+        members.add(new Member("Alice", 50));
+        members.add(new Member("Bob", 60));
+
+        assertThat(members).haveExactly(1, senior);
+        assertThat(members).doNotHave(nameJohn);
+    }
+
+    @Test
+    public void whenCombiningAllOfConditions_thenCorrect() {
+        Member john = new Member("John", 60);
+        Member jane = new Member("Jane", 50);
+
+        assertThat(john).is(allOf(senior, nameJohn));
+        assertThat(jane).is(allOf(not(nameJohn), not(senior)));
+    }
+
+    @Test
+    public void whenCombiningAnyOfConditions_thenCorrect() {
+        Member john = new Member("John", 50);
+        Member jane = new Member("Jane", 60);
+
+        assertThat(john).is(anyOf(senior, nameJohn));
+        assertThat(jane).is(anyOf(nameJohn, senior));
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/AssertJCoreUnitTest.java

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+package com.baeldung.assertj;
+
+import org.assertj.core.util.Maps;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+import static org.assertj.core.api.Assertions.*;
+
+public class AssertJCoreUnitTest {
+
+    @Test
+    public void whenComparingReferences_thenNotEqual() throws Exception {
+        Dog fido = new Dog("Fido", 5.15f);
+        Dog fidosClone = new Dog("Fido", 5.15f);
+
+        assertThat(fido).isNotEqualTo(fidosClone);
+    }
+
+    @Test
+    public void whenComparingFields_thenEqual() throws Exception {
+        Dog fido = new Dog("Fido", 5.15f);
+        Dog fidosClone = new Dog("Fido", 5.15f);
+
+        assertThat(fido).isEqualToComparingFieldByFieldRecursively(fidosClone);
+    }
+
+    @Test
+    public void whenCheckingForElement_thenContains() throws Exception {
+        List<String> list = Arrays.asList("1", "2", "3");
+
+        assertThat(list).contains("1");
+    }
+
+    @Test
+    public void whenCheckingForElement_thenMultipleAssertions() throws Exception {
+        List<String> list = Arrays.asList("1", "2", "3");
+
+        assertThat(list).isNotEmpty();
+        assertThat(list).startsWith("1");
+        assertThat(list).doesNotContainNull();
+
+        assertThat(list).isNotEmpty().contains("1").startsWith("1").doesNotContainNull().containsSequence("2", "3");
+    }
+
+    @Test
+    public void whenCheckingRunnable_thenIsInterface() throws Exception {
+        assertThat(Runnable.class).isInterface();
+    }
+
+    @Test
+    public void whenCheckingCharacter_thenIsUnicode() throws Exception {
+        char someCharacter = 'c';
+
+        assertThat(someCharacter).isNotEqualTo('a').inUnicode().isGreaterThanOrEqualTo('b').isLowerCase();
+    }
+
+    @Test
+    public void whenAssigningNSEExToException_thenIsAssignable() throws Exception {
+        assertThat(Exception.class).isAssignableFrom(NoSuchElementException.class);
+    }
+
+    @Test
+    public void whenComparingWithOffset_thenEquals() throws Exception {
+        assertThat(5.1).isEqualTo(5, withPrecision(1d));
+    }
+
+    @Test
+    public void whenCheckingString_then() throws Exception {
+        assertThat("".isEmpty()).isTrue();
+    }
+
+    @Test
+    public void whenCheckingFile_then() throws Exception {
+        final File someFile = File.createTempFile("aaa", "bbb");
+        someFile.deleteOnExit();
+
+        assertThat(someFile).exists().isFile().canRead().canWrite();
+    }
+
+    @Test
+    public void whenCheckingIS_then() throws Exception {
+        InputStream given = new ByteArrayInputStream("foo".getBytes());
+        InputStream expected = new ByteArrayInputStream("foo".getBytes());
+
+        assertThat(given).hasSameContentAs(expected);
+    }
+
+    @Test
+    public void whenGivenMap_then() throws Exception {
+        Map<Integer, String> map = Maps.newHashMap(2, "a");
+
+        assertThat(map).isNotEmpty().containsKey(2).doesNotContainKeys(10).contains(entry(2, "a"));
+    }
+
+    @Test
+    public void whenGivenException_then() throws Exception {
+        Exception ex = new Exception("abc");
+
+        assertThat(ex).hasNoCause().hasMessageEndingWith("c");
+    }
+
+    @Ignore // IN ORDER TO TEST, REMOVE THIS LINE
+    @Test
+    public void whenRunningAssertion_thenDescribed() throws Exception {
+        Person person = new Person("Alex", 34);
+
+        assertThat(person.getAge()).as("%s's age should be equal to 100").isEqualTo(100);
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/AssertJGuavaUnitTest.java

@@ -0,0 +1,96 @@
+package com.baeldung.assertj;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.HashBasedTable;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Multimaps;
+import com.google.common.collect.Range;
+import com.google.common.collect.Table;
+import com.google.common.collect.TreeRangeMap;
+import com.google.common.io.Files;
+import org.assertj.guava.data.MapEntry;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.HashMap;
+import java.util.HashSet;
+
+import static org.assertj.guava.api.Assertions.assertThat;
+import static org.assertj.guava.api.Assertions.entry;
+
+public class AssertJGuavaUnitTest {
+
+    @Test
+    public void givenTwoEmptyFiles_whenComparingContent_thenEqual() throws Exception {
+        final File temp1 = File.createTempFile("bael", "dung1");
+        final File temp2 = File.createTempFile("bael", "dung2");
+
+        assertThat(Files.asByteSource(temp1)).hasSize(0).hasSameContentAs(Files.asByteSource(temp2));
+    }
+
+    @Test
+    public void givenMultimap_whenVerifying_thenCorrect() throws Exception {
+        final Multimap<Integer, String> mmap = ArrayListMultimap.create();
+        mmap.put(1, "one");
+        mmap.put(1, "1");
+
+        assertThat(mmap).hasSize(2).containsKeys(1).contains(entry(1, "one")).contains(entry(1, "1"));
+    }
+
+    @Test
+    public void givenMultimaps_whenVerifyingContent_thenCorrect() throws Exception {
+        final Multimap<Integer, String> mmap1 = ArrayListMultimap.create();
+        mmap1.put(1, "one");
+        mmap1.put(1, "1");
+        mmap1.put(2, "two");
+        mmap1.put(2, "2");
+
+        final Multimap<Integer, String> mmap1_clone = Multimaps.newSetMultimap(new HashMap<>(), HashSet::new);
+        mmap1_clone.put(1, "one");
+        mmap1_clone.put(1, "1");
+        mmap1_clone.put(2, "two");
+        mmap1_clone.put(2, "2");
+
+        final Multimap<Integer, String> mmap2 = Multimaps.newSetMultimap(new HashMap<>(), HashSet::new);
+        mmap2.put(1, "one");
+        mmap2.put(1, "1");
+
+        assertThat(mmap1).containsAllEntriesOf(mmap2).containsAllEntriesOf(mmap1_clone).hasSameEntriesAs(mmap1_clone);
+    }
+
+    @Test
+    public void givenOptional_whenVerifyingContent_thenShouldBeEqual() throws Exception {
+        final Optional<String> something = Optional.of("something");
+
+        assertThat(something).isPresent().extractingValue().isEqualTo("something");
+    }
+
+    @Test
+    public void givenRange_whenVerifying_thenShouldBeCorrect() throws Exception {
+        final Range<String> range = Range.openClosed("a", "g");
+
+        assertThat(range).hasOpenedLowerBound().isNotEmpty().hasClosedUpperBound().contains("b");
+    }
+
+    @Test
+    public void givenRangeMap_whenVerifying_thenShouldBeCorrect() throws Exception {
+        final TreeRangeMap<Integer, String> map = TreeRangeMap.create();
+
+        map.put(Range.closed(0, 60), "F");
+        map.put(Range.closed(61, 70), "D");
+
+        assertThat(map).isNotEmpty().containsKeys(0).contains(MapEntry.entry(34, "F"));
+    }
+
+    @Test
+    public void givenTable_whenVerifying_thenShouldBeCorrect() throws Exception {
+        final Table<Integer, String, String> table = HashBasedTable.create(2, 2);
+
+        table.put(1, "A", "PRESENT");
+        table.put(1, "B", "ABSENT");
+
+        assertThat(table).hasRowCount(1).containsValues("ABSENT").containsCell(1, "B", "ABSENT");
+    }
+
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/AssertJJava8UnitTest.java

@@ -0,0 +1,108 @@
+package com.baeldung.assertj;
+
+import org.junit.Test;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Predicate;
+
+import static java.time.LocalDate.ofYearDay;
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class AssertJJava8UnitTest {
+
+    @Test
+    public void givenOptional_shouldAssert() throws Exception {
+        final Optional<String> givenOptional = Optional.of("something");
+
+        assertThat(givenOptional).isPresent().hasValue("something");
+    }
+
+    @Test
+    public void givenPredicate_shouldAssert() throws Exception {
+        final Predicate<String> predicate = s -> s.length() > 4;
+
+        assertThat(predicate).accepts("aaaaa", "bbbbb").rejects("a", "b").acceptsAll(asList("aaaaa", "bbbbb")).rejectsAll(asList("a", "b"));
+    }
+
+    @Test
+    public void givenLocalDate_shouldAssert() throws Exception {
+        final LocalDate givenLocalDate = LocalDate.of(2016, 7, 8);
+        final LocalDate todayDate = LocalDate.now();
+
+        assertThat(givenLocalDate).isBefore(LocalDate.of(2020, 7, 8)).isAfterOrEqualTo(LocalDate.of(1989, 7, 8));
+
+        assertThat(todayDate).isAfter(LocalDate.of(1989, 7, 8)).isToday();
+    }
+
+    @Test
+    public void givenLocalDateTime_shouldAssert() throws Exception {
+        final LocalDateTime givenLocalDate = LocalDateTime.of(2016, 7, 8, 12, 0);
+
+        assertThat(givenLocalDate).isBefore(LocalDateTime.of(2020, 7, 8, 11, 2));
+    }
+
+    @Test
+    public void givenLocalTime_shouldAssert() throws Exception {
+        final LocalTime givenLocalTime = LocalTime.of(12, 15);
+
+        assertThat(givenLocalTime).isAfter(LocalTime.of(1, 0)).hasSameHourAs(LocalTime.of(12, 0));
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtracting() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList).flatExtracting(LocalDate::getYear).contains(2015);
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtractingLeapYear() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList).flatExtracting(LocalDate::isLeapYear).contains(true);
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtractingClass() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList).flatExtracting(Object::getClass).contains(LocalDate.class);
+    }
+
+    @Test
+    public void givenList_shouldAssertMultipleFlatExtracting() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList).flatExtracting(LocalDate::getYear, LocalDate::getDayOfMonth).contains(2015, 6);
+    }
+
+    @Test
+    public void givenString_shouldSatisfy() throws Exception {
+        final String givenString = "someString";
+
+        assertThat(givenString).satisfies(s -> {
+            assertThat(s).isNotEmpty();
+            assertThat(s).hasSize(10);
+        });
+    }
+
+    @Test
+    public void givenString_shouldMatch() throws Exception {
+        final String emptyString = "";
+
+        assertThat(emptyString).matches(String::isEmpty);
+    }
+
+    @Test
+    public void givenList_shouldHasOnlyOneElementSatisfying() throws Exception {
+        final List<String> givenList = Arrays.asList("");
+
+        assertThat(givenList).hasOnlyOneElementSatisfying(s -> assertThat(s).isEmpty());
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/custom/AssertJCustomAssertionsUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.assertj.custom;
+
+import static com.baeldung.assertj.custom.Assertions.assertThat;
+import static org.junit.Assert.fail;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class AssertJCustomAssertionsUnitTest {
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    @Test
+    public void whenPersonNameMatches_thenCorrect() {
+        Person person = new Person("John Doe", 20);
+        assertThat(person).hasFullName("John Doe");
+    }
+
+    @Test
+    public void whenPersonAgeLessThanEighteen_thenNotAdult() {
+        Person person = new Person("Jane Roe", 16);
+
+        try {
+            assertThat(person).isAdult();
+            fail();
+        } catch (AssertionError e) {
+            org.assertj.core.api.Assertions.assertThat(e).hasMessage("Expected person to be adult");
+        }
+    }
+
+    @Test
+    public void whenPersonDoesNotHaveAMatchingNickname_thenIncorrect() {
+        Person person = new Person("John Doe", 20);
+        person.addNickname("Nick");
+
+        try {
+            assertThat(person).hasNickname("John");
+            fail();
+        } catch (AssertionError e) {
+            org.assertj.core.api.Assertions.assertThat(e).hasMessage("Expected person to have nickname John");
+        }
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/custom/Assertions.java

@@ -0,0 +1,9 @@
+package com.baeldung.assertj.custom;
+
+public class Assertions {
+    public static PersonAssert assertThat(Person actual) {
+        return new PersonAssert(actual);
+    }
+
+    // static factory methods of other assertion classes
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/custom/PersonAssert.java

@@ -0,0 +1,38 @@
+package com.baeldung.assertj.custom;
+
+import org.assertj.core.api.AbstractAssert;
+
+public class PersonAssert extends AbstractAssert<PersonAssert, Person> {
+
+    public PersonAssert(Person actual) {
+        super(actual, PersonAssert.class);
+    }
+
+    public static PersonAssert assertThat(Person actual) {
+        return new PersonAssert(actual);
+    }
+
+    public PersonAssert hasFullName(String fullName) {
+        isNotNull();
+        if (!actual.getFullName().equals(fullName)) {
+            failWithMessage("Expected person to have full name %s but was %s", fullName, actual.getFullName());
+        }
+        return this;
+    }
+
+    public PersonAssert isAdult() {
+        isNotNull();
+        if (actual.getAge() < 18) {
+            failWithMessage("Expected person to be adult");
+        }
+        return this;
+    }
+
+    public PersonAssert hasNickname(String nickName) {
+        isNotNull();
+        if (!actual.getNicknames().contains(nickName)) {
+            failWithMessage("Expected person to have nickname %s", nickName);
+        }
+        return this;
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/exceptions/Java7StyleAssertions.java

@@ -0,0 +1,24 @@
+package com.baeldung.assertj.exceptions;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.failBecauseExceptionWasNotThrown;
+
+import org.junit.Test;
+
+public class Java7StyleAssertions {
+
+    @Test
+    public void whenDividingByZero_thenArithmeticException() {
+        try {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+            fail("ArithmeticException expected because dividing by zero yields an ArithmeticException.");
+            failBecauseExceptionWasNotThrown(ArithmeticException.class);
+        } catch (Exception e) {
+            assertThat(e).hasMessage("/ by zero");
+            assertThat(e).isInstanceOf(ArithmeticException.class);
+        }
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/assertj/exceptions/Java8StyleAssertions.java

@@ -0,0 +1,66 @@
+package com.baeldung.assertj.exceptions;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.catchThrowable;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.junit.Test;
+
+public class Java8StyleAssertions {
+
+    @Test
+    public void whenGettingOutOfBoundsItem_thenIndexOutOfBoundsException() {
+        assertThatThrownBy(() -> {
+            ArrayList<String> myStringList = new ArrayList<String>(Arrays.asList("Strine one", "String two"));
+            myStringList.get(2);
+        }).isInstanceOf(IndexOutOfBoundsException.class)
+            .hasMessageStartingWith("Index: 2")
+            .hasMessageContaining("2")
+            .hasMessageEndingWith("Size: 2")
+            .hasMessageContaining("Index: 2, Size: 2")
+            .hasMessage("Index: %s, Size: %s", 2, 2)
+            .hasMessageMatching("Index: \\d+, Size: \\d+")
+            .hasNoCause();
+    }
+
+    @Test
+    public void whenWrappingException_thenCauseInstanceOfWrappedExceptionType() {
+        assertThatThrownBy(() -> {
+            try {
+                throw new IOException();
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }).isInstanceOf(RuntimeException.class)
+            .hasCauseInstanceOf(IOException.class)
+            .hasStackTraceContaining("IOException");
+    }
+
+    @Test
+    public void whenDividingByZero_thenArithmeticException() {
+        assertThatExceptionOfType(ArithmeticException.class).isThrownBy(() -> {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+        })
+            .withMessageContaining("/ by zero");
+
+        // Alternatively:
+
+        // when
+        Throwable thrown = catchThrowable(() -> {
+            int numerator = 10;
+            int denominator = 0;
+            int quotient = numerator / denominator;
+        });
+
+        // then
+        assertThat(thrown).isInstanceOf(ArithmeticException.class)
+            .hasMessageContaining("/ by zero");
+
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/jgotesting/JGoTestingUnitTest.java

@@ -0,0 +1,93 @@
+package com.baeldung.testing.jgotesting;
+
+import java.io.File;
+import static org.hamcrest.Matchers.equalToIgnoringCase;
+import static org.hamcrest.Matchers.is;
+import org.jgotesting.rule.JGoTestRule;
+import static org.jgotesting.Assert.*; // same methods as org.junit.Assert.*
+import static org.jgotesting.Check.*; // ditto, with different names
+import static org.jgotesting.Testing.*;
+import org.jgotesting.Checker;
+import org.junit.Ignore;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class JGoTestingUnitTest {
+    @Rule
+    public final JGoTestRule test = new JGoTestRule();
+
+    @Test
+    public void whenComparingIntegers_thenEqual() {
+        int anInt = 10;
+
+        assertEquals(anInt, 10);
+        checkEquals(anInt, 10);
+    }
+
+    @Ignore
+    @Test
+    public void whenComparingNumbers_thenLoggedMessage() {
+        log("There was something wrong when comparing numbers");
+
+        int anInt = 10;
+        int anotherInt = 10;
+
+        checkEquals(anInt, 10);
+        checkTrue("First number should be bigger", 10 > anotherInt);
+        checkSame(anInt, anotherInt);
+    }
+
+    @Ignore
+    @Test
+    public void whenComparingNumbers_thenFormattedMessage() {
+        int anInt = 10;
+        int anotherInt = 10;
+
+        logf("There was something wrong when comparing numbers %d and %d", anInt, anotherInt);
+
+        checkEquals(anInt, 10);
+        checkTrue("First number should be bigger", 10 > anotherInt);
+        checkSame(anInt, anotherInt);
+    }
+
+    @Test
+    public void whenComparingStrings_thenMultipleAssertions() {
+        String aString = "This is a string";
+        String anotherString = "This Is A String";
+
+        test.check(aString, equalToIgnoringCase(anotherString))
+            .check(aString.length() == 16)
+            .check(aString.startsWith("This"));
+    }
+
+    @Ignore
+    @Test
+    public void whenComparingStrings_thenMultipleFailingAssertions() {
+        String aString = "the test string";
+        String anotherString = "The Test String";
+
+        checkEquals("Strings are not equal!", aString, anotherString);
+        checkTrue("String is longer than one character", aString.length() == 1);
+        checkSame("Strings are not the same", aString, anotherString);
+    }
+
+    @Ignore
+    @Test
+    public void givenFile_whenDoesnotExists_thenTerminated() throws Exception {
+        File aFile = new File("a_dummy_file.txt");
+        terminateIf(aFile.exists(), is(false));
+
+        // This doesn't get executed
+        checkEquals(aFile.getName(), "a_dummy_file.txt");
+    }
+
+    @Test
+    public void givenChecker_whenComparingStrings_thenEqual() throws Exception {
+        Checker<String> aChecker = s -> s.matches("\\d+");
+
+        String aString = "1235";
+        test.check(aString, aChecker);
+    }
+
+}
+

testing-modules/assertion-libraries/src/test/java/com/baeldung/jspec/CageUnitTest.java

@@ -0,0 +1,126 @@
+package com.baeldung.jspec;
+
+import static org.javalite.test.jspec.JSpec.$;
+import static org.javalite.test.jspec.JSpec.expect;
+import static org.javalite.test.jspec.JSpec.the;
+
+import java.util.Set;
+
+import org.javalite.test.jspec.DifferenceExpectation;
+import org.junit.Test;
+
+public class CageUnitTest {
+
+    Cat tomCat = new Cat("Tom");
+    Cat felixCat = new Cat("Felix");
+    Dog boltDog = new Dog("Bolt");
+    Cage cage = new Cage();
+
+    
+    @Test
+    public void puttingAnimals_shouldIncreaseCageSize() {
+        // When
+        cage.put(tomCat, boltDog);
+        
+        // Then
+        the(cage.size()).shouldEqual(2);
+    }
+    
+    @Test
+    public void releasingAnimals_shouldDecreaseCageSize() {
+        // When
+        cage.put(tomCat, boltDog);
+        cage.release(tomCat);
+        
+        // Then
+        the(cage.size()).shouldEqual(1);
+    }
+    
+    @Test
+    public void puttingAnimals_shouldLeaveThemInsideTheCage() {
+        // When
+        cage.put(tomCat, boltDog);
+        
+        // Then
+        the(cage).shouldHave("animals");
+    }
+    
+    @Test
+    public void openingTheCage_shouldReleaseAllAnimals() {
+        // When
+        cage.put(tomCat, boltDog);
+        
+        // Then
+        the(cage).shouldNotBe("empty");
+        
+        // When
+        cage.open();
+        
+        // Then
+        the(cage).shouldBe("empty");
+        the(cage.isEmpty()).shouldBeTrue();
+    }
+    
+    @Test
+    public void comparingTwoDogs() {
+        // When
+        Dog firstDog = new Dog("Rex");
+        Dog secondDog = new Dog("Rex");
+        
+        // Then
+        $(firstDog).shouldEqual(secondDog);
+        $(firstDog).shouldNotBeTheSameAs(secondDog);
+    }
+    
+    @Test
+    public void puttingCatsOnly_shouldLetCageAnimalsToContainCats() {
+        // When
+        cage.put(tomCat, felixCat);
+        
+        // Then
+        Set<Animal> animals = cage.getAnimals();
+        the(animals).shouldContain(tomCat);
+        the(animals).shouldContain(felixCat);
+        the(animals).shouldNotContain(boltDog);
+    }
+    
+    @Test
+    public void puttingCatsOnly_shouldLetCageToContainCats() {
+        // When
+        cage.put(tomCat, felixCat);
+        
+        // Then
+        // Check with toString of the tested objects
+        the(cage).shouldContain(tomCat);
+        the(cage).shouldContain(felixCat);
+        the(cage).shouldNotContain(boltDog);
+    }
+    
+    @Test
+    public void puttingMoreAnimals_shouldChangeSize() {
+        // When
+        cage.put(tomCat, boltDog);
+        
+        // Then
+        expect( new DifferenceExpectation<Integer>(cage.size()) {
+
+            @Override
+            public Integer exec() {
+                cage.release(tomCat);
+                return cage.size();
+            }
+        } );
+    }
+    
+    
+    @Test
+    public void releasingTheDog_shouldReleaseAnAnimalOfDogType() {
+        // When
+        cage.put(boltDog);
+        Animal releasedAnimal = cage.release(boltDog);
+        
+        // Then
+        the(releasedAnimal).shouldNotBeNull();
+        the(releasedAnimal).shouldBeA(Dog.class);
+    }
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/jspec/JSpecUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.jspec;
+
+import static org.javalite.test.jspec.JSpec.$;
+import static org.javalite.test.jspec.JSpec.a;
+import static org.javalite.test.jspec.JSpec.expect;
+import static org.javalite.test.jspec.JSpec.it;
+import static org.javalite.test.jspec.JSpec.the;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.javalite.test.jspec.ExceptionExpectation;
+import org.junit.Test;
+
+public class JSpecUnitTest {
+
+    @Test
+    public void onePlusTwo_shouldEqualThree() {
+        $(1 + 2).shouldEqual(3);
+        a(1 + 2).shouldEqual(3);
+        the(1 + 2).shouldEqual(3);
+        it(1 + 2).shouldEqual(3);
+    }
+    
+    @Test
+    public void messageShouldContainJSpec() {
+        String message = "Welcome to JSpec demo";
+        // The message should not be empty
+        the(message).shouldNotBe("empty");
+        // The message should contain JSpec
+        the(message).shouldContain("JSpec");
+    }
+
+    public void colorsListShouldContainRed() {
+        List<String> colorsList = Arrays.asList("red", "green", "blue");
+        $(colorsList).shouldContain("red");
+    }
+
+    public void guessedNumberShouldEqualHiddenNumber() {
+        Integer guessedNumber = 11;
+        Integer hiddenNumber = 11;
+
+        $(guessedNumber).shouldEqual(hiddenNumber);
+        $(guessedNumber).shouldNotBeTheSameAs(hiddenNumber);
+    }
+    
+    @Test
+    public void dividingByThero_shouldThrowArithmeticException() {
+        expect(new ExceptionExpectation<ArithmeticException>(ArithmeticException.class) {
+            @Override
+            public void exec() throws ArithmeticException {
+                System.out.println(1 / 0);
+            }
+        } );
+    }
+
+}

testing-modules/assertion-libraries/src/test/java/com/baeldung/truth/GoogleTruthUnitTest.java

@@ -0,0 +1,561 @@
+package com.baeldung.truth;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Range;
+import com.google.common.collect.Table;
+import com.google.common.collect.TreeBasedTable;
+import com.google.common.collect.TreeMultiset;
+import static com.baeldung.truth.UserSubject.*;
+import static com.google.common.truth.Truth.*;
+import static com.google.common.truth.Truth8.*;
+import java.math.BigDecimal;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map; 
+import java.util.Optional;
+import java.util.Set;
+import java.util.regex.Pattern;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class GoogleTruthUnitTest {
+
+    @Test
+    public void whenComparingInteger_thenEqual() {
+        int anInt = 10;
+
+        assertThat(anInt).isEqualTo(10);
+    }
+
+    @Test
+    public void whenComparingFloat_thenIsBigger() {
+        float aFloat = 10.0f;
+
+        assertThat(aFloat).isGreaterThan(1.0f);
+    }
+
+    @Test
+    public void whenComparingDouble_thenIsSmaller() {
+        double aDouble = 10.0f;
+
+        assertThat(aDouble).isLessThan(20.0);
+    }
+
+    @Test
+    public void whenComparingFloat_thenWithinPrecision() {
+        float aFloat = 23.04f;
+
+        assertThat(aFloat).isWithin(1.3f)
+            .of(23.3f);
+    }
+
+    @Test
+    public void whenComparingFloat_thenNotWithinPrecision() {
+        float aFloat = 23.04f;
+
+        assertThat(aFloat).isNotWithin(1.3f)
+            .of(100f);
+    }
+
+    @Test
+    public void whenComparingDouble_thenWithinPrecision() {
+        double aDouble = 22.18;
+
+        assertThat(aDouble).isWithin(2)
+            .of(23d);
+    }
+
+    @Test
+    public void whenComparingDouble_thenNotWithinPrecision() {
+        double aDouble = 22.08;
+
+        assertThat(aDouble).isNotWithin(2)
+            .of(100);
+    }
+
+    @Test
+    public void whenComparingBigDecimal_thenEqualIgnoringScale() {
+        BigDecimal aBigDecimal = BigDecimal.valueOf(1000, 3);
+
+        assertThat(aBigDecimal).isEqualToIgnoringScale(new BigDecimal(1.0));
+    }
+
+    @Test
+    public void whenCheckingBoolean_thenTrue() {
+        boolean aBoolean = true;
+
+        assertThat(aBoolean).isTrue();
+    }
+
+    @Test
+    public void whenCheckingBoolean_thenFalse() {
+        boolean aBoolean = false;
+
+        assertThat(aBoolean).isFalse();
+    }
+
+    @Test
+    public void whenComparingArrays_thenEqual() {
+        String[] firstArrayOfStrings = { "one", "two", "three" };
+        String[] secondArrayOfStrings = { "one", "two", "three" };
+
+        assertThat(firstArrayOfStrings).isEqualTo(secondArrayOfStrings);
+    }
+
+    @Test
+    public void whenComparingArrays_thenNotEqual() {
+        String[] firstArrayOfStrings = { "one", "two", "three" };
+        String[] secondArrayOfStrings = { "three", "two", "one" };
+
+        assertThat(firstArrayOfStrings).isNotEqualTo(secondArrayOfStrings);
+    }
+
+    @Test
+    public void whenCheckingArray_thenEmpty() {
+        Object[] anArray = {};
+
+        assertThat(anArray).isEmpty();
+    }
+
+    @Test
+    public void whenCheckingArray_thenNotEmpty() {
+        String[] arrayOfStrings = { "One String " };
+
+        assertThat(arrayOfStrings).isNotEmpty();
+    }
+
+    @Test
+    public void whenCheckingArrayOfDoubles_thenWithinPrecision() {
+        double[] arrayOfDoubles = { 1, 2, 3, 4, 5 };
+
+        assertThat(arrayOfDoubles).hasValuesWithin(5)
+            .of(6, 7, 8, 9, 10);
+    }
+
+    @Test
+    public void whenComparingUsers_thenEqual() {
+        User aUser = new User("John Doe");
+        User anotherUser = new User("John Doe");
+
+        assertThat(aUser).isEqualTo(anotherUser);
+    }
+
+    @Test
+    public void whenComparingUser_thenIsNull() {
+        User aUser = null;
+
+        assertThat(aUser).isNull();
+    }
+
+    @Test
+    public void whenComparingUser_thenNotNull() {
+        User aUser = new User();
+
+        assertThat(aUser).isNotNull();
+    }
+
+    @Test
+    public void whenComparingUser_thenInstanceOf() {
+        User aUser = new User();
+
+        assertThat(aUser).isInstanceOf(User.class);
+    }
+
+    @Test
+    public void whenComparingUser_thenInList() {
+        User aUser = new User();
+
+        assertThat(aUser).isIn(Arrays.asList(1, 3, aUser, null));
+    }
+
+    @Test
+    public void whenComparingUser_thenNotInList() {
+        User aUser = new User();
+
+        assertThat(aUser).isNotIn(Arrays.asList(1, 3, "Three"));
+    }
+
+    @Test
+    public void whenComparingNullUser_thenInList() {
+        User aUser = null;
+        User anotherUser = new User();
+
+        assertThat(aUser).isIn(Arrays.asList(1, 3, anotherUser, null));
+    }
+
+    @Test
+    public void whenCheckingString_thenStartsWithString() {
+        String aString = "This is a string";
+
+        assertThat(aString).startsWith("This");
+    }
+
+    @Test
+    public void whenCheckingString_thenContainsString() {
+        String aString = "This is a string";
+
+        assertThat(aString).contains("is a");
+    }
+
+    @Test
+    public void whenCheckingString_thenEndsWithString() {
+        String aString = "This is a string";
+
+        assertThat(aString).endsWith("string");
+    }
+
+    @Test
+    public void whenCheckingString_thenExpectedLength() {
+        String aString = "This is a string";
+
+        assertThat(aString).hasLength(16);
+    }
+
+    @Test
+    public void whenCheckingString_thenEmpty() {
+        String aString = "";
+
+        assertThat(aString).isEmpty();
+    }
+
+    @Test
+    public void whenCheckingString_thenMatches() {
+        String aString = "The string to match";
+
+        assertThat(aString).matches(Pattern.compile("[a-zA-Z\\s]+"));
+    }
+
+    @Test
+    public void whenCheckingComparable_thenAtLeast() {
+        Comparable<Integer> aComparable = 5;
+
+        assertThat(aComparable).isAtLeast(1);
+    }
+
+    @Test
+    public void whenCheckingComparable_thenAtMost() {
+        Comparable<Integer> aComparable = 5;
+
+        assertThat(aComparable).isAtMost(10);
+    }
+
+    @Test
+    public void whenCheckingComparable_thenInList() {
+        Comparable<Integer> aComparable = 5;
+
+        assertThat(aComparable).isIn(Arrays.asList(4, 5, 6));
+    }
+
+    @Test
+    public void whenCheckingComparable_thenInRange() {
+        Comparable<Integer> aComparable = 5;
+
+        assertThat(aComparable).isIn(Range.closed(1, 10));
+    }
+
+    @Test
+    public void whenCheckingComparable_thenNotInRange() {
+        Comparable<Integer> aComparable = 5;
+
+        assertThat(aComparable).isNotIn(Range.closed(10, 15));
+    }
+
+    @Test
+    public void whenComparingUsers_thenEquivalent() {
+        User aUser = new User();
+        aUser.setName("John Doe");
+
+        User anotherUser = new User();
+        anotherUser.setName("john doe");
+
+        assertThat(aUser).isEquivalentAccordingToCompareTo(anotherUser);
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContains() {
+        List<Integer> aList = Arrays.asList(4, 5, 6);
+
+        assertThat(aList).contains(5);
+    }
+
+    @Test
+    public void whenCheckingIterable_thenDoesNotContains() {
+        List<Integer> aList = Arrays.asList(4, 5, 6);
+
+        assertThat(aList).doesNotContain(9);
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContainsAny() {
+        List<Integer> aList = Arrays.asList(4, 5, 6);
+
+        assertThat(aList).containsAnyOf(0, 5, 10);
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContainsAnyInList() {
+        List<Integer> aList = Arrays.asList(1, 2, 3);
+
+        assertThat(aList).containsAnyIn(Arrays.asList(1, 5, 10));
+    }
+
+    @Test
+    public void whenCheckingIterable_thenNoDuplicates() {
+        List<Integer> aList = Arrays.asList(-2, -1, 0, 1, 2);
+
+        assertThat(aList).containsNoDuplicates();
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContainsNoneOf() {
+        List<Integer> aList = Arrays.asList(4, 5, 6);
+
+        assertThat(aList).containsNoneOf(9, 8, 7);
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContainsNoneIn() {
+        List<Integer> aList = Arrays.asList(4, 5, 6);
+
+        assertThat(aList).containsNoneIn(Arrays.asList(9, 10, 11));
+    }
+
+    @Test
+    public void whenCheckingIterable_thenContainsExactElements() {
+        List<String> aList = Arrays.asList("10", "20", "30");
+        List<String> anotherList = Arrays.asList("10", "20", "30");
+
+        assertThat(aList).containsExactlyElementsIn(anotherList)
+            .inOrder();
+    }
+
+    @Test
+    public void whenCheckingIterable_thenOrdered() {
+        Set<String> aSet = new LinkedHashSet<>(Arrays.asList("one", "three", "two"));
+
+        assertThat(aSet).isOrdered();
+    }
+
+    @Test
+    public void givenComparator_whenCheckingIterable_thenOrdered() {
+        Comparator<String> aComparator = (a, b) -> new Float(a).compareTo(new Float(b));
+
+        List<String> aList = Arrays.asList("1", "012", "0020", "100");
+
+        assertThat(aList).isOrdered(aComparator);
+    }
+
+    @Test
+    public void whenCheckingMap_thenContainsEntry() {
+        Map<String, Object> aMap = new HashMap<>();
+        aMap.put("one", 1L);
+
+        assertThat(aMap).containsEntry("one", 1L);
+    }
+
+    @Test
+    public void whenCheckingMap_thenContainsKey() {
+        Map<String, Object> map = new HashMap<>();
+        map.put("one", 1L);
+
+        assertThat(map).containsKey("one");
+    }
+
+    @Test
+    public void whenCheckingMap_thenContainsEntries() {
+        Map<String, Object> aMap = new HashMap<>();
+        aMap.put("first", 1L);
+        aMap.put("second", 2.0);
+        aMap.put("third", 3f);
+
+        Map<String, Object> anotherMap = new HashMap<>(aMap);
+
+        assertThat(aMap).containsExactlyEntriesIn(anotherMap);
+    }
+
+    @Test
+    public void whenCheckingException_thenInstanceOf() {
+        Exception anException = new IllegalArgumentException(new NumberFormatException());
+
+        assertThat(anException).hasCauseThat()
+            .isInstanceOf(NumberFormatException.class);
+    }
+
+    @Test
+    public void whenCheckingException_thenCauseMessageIsKnown() {
+        Exception anException = new IllegalArgumentException("Bad value");
+
+        assertThat(anException).hasMessageThat()
+            .startsWith("Bad");
+    }
+
+    @Test
+    public void whenCheckingClass_thenIsAssignable() {
+        Class<Double> aClass = Double.class;
+
+        assertThat(aClass).isAssignableTo(Number.class);
+    }
+
+    // Java 8 Tests
+    @Test
+    public void whenCheckingJavaOptional_thenHasValue() {
+        Optional<Integer> anOptional = Optional.of(1);
+
+        assertThat(anOptional).hasValue(1);
+    }
+
+    @Test
+    public void whenCheckingJavaOptional_thenPresent() {
+        Optional<String> anOptional = Optional.of("Baeldung");
+
+        assertThat(anOptional).isPresent();
+    }
+
+    @Test
+    public void whenCheckingJavaOptional_thenEmpty() {
+        Optional anOptional = Optional.empty();
+
+        assertThat(anOptional).isEmpty();
+    }
+
+    @Test
+    public void whenCheckingStream_thenContainsInOrder() {
+        Stream<Integer> anStream = Stream.of(1, 2, 3);
+
+        assertThat(anStream).containsAllOf(1, 2, 3)
+            .inOrder();
+    }
+
+    @Test
+    public void whenCheckingStream_thenDoesNotContain() {
+        Stream<Integer> anStream = IntStream.range(1, 100)
+            .boxed();
+
+        assertThat(anStream).doesNotContain(0);
+    }
+
+    // Guava Tests
+    @Test
+    public void whenCheckingGuavaOptional_thenIsAbsent() {
+        com.google.common.base.Optional anOptional = com.google.common.base.Optional.absent();
+
+        assertThat(anOptional).isAbsent();
+    }
+
+    @Test
+    public void whenCheckingGuavaMultimap_thenExpectedSize() {
+        Multimap<String, Object> aMultimap = ArrayListMultimap.create();
+        aMultimap.put("one", 1L);
+        aMultimap.put("one", 2.0);
+
+        assertThat(aMultimap).valuesForKey("one")
+            .hasSize(2);
+    }
+
+    @Test
+    public void whenCheckingGuavaMultiset_thenExpectedCount() {
+        TreeMultiset<String> aMultiset = TreeMultiset.create();
+        aMultiset.add("baeldung", 10);
+
+        assertThat(aMultiset).hasCount("baeldung", 10);
+    }
+
+    @Test
+    public void whenCheckingGuavaTable_thenContains() {
+        Table<String, String, String> aTable = getDummyGuavaTable();
+
+        assertThat(aTable).contains("firstRow", "firstColumn");
+    }
+
+    @Test
+    public void whenCheckingGuavaTable_thenContainsCell() {
+        Table<String, String, String> aTable = getDummyGuavaTable();
+
+        assertThat(aTable).containsCell("firstRow", "firstColumn", "baeldung");
+    }
+
+    @Test
+    public void whenCheckingGuavaTable_thenContainsRow() {
+        Table<String, String, String> aTable = getDummyGuavaTable();
+
+        assertThat(aTable).containsRow("firstRow");
+    }
+
+    @Test
+    public void whenCheckingGuavaTable_thenContainsColumn() {
+        Table<String, String, String> aTable = getDummyGuavaTable();
+
+        assertThat(aTable).containsColumn("firstColumn");
+    }
+
+    @Test
+    public void whenCheckingGuavaTable_thenContainsValue() {
+        Table<String, String, String> aTable = getDummyGuavaTable();
+
+        assertThat(aTable).containsValue("baeldung");
+    }
+
+    @Ignore
+    @Test
+    public void whenFailingAssertion_thenMessagePrefix() {
+        User aUser = new User();
+
+        assertThat(aUser).named("User [%s]", aUser.getName())
+            .isNull();
+    }
+
+    @Ignore
+    @Test
+    public void whenFailingAssertion_thenCustomMessage() {
+        User aUser = new User();
+
+        assertWithMessage("TEST-985: Secret user subject was NOT null!").that(aUser)
+            .isNull();
+    }
+
+    @Ignore
+    @Test
+    public void whenFailingAssertion_thenCustomMessageAndPrefix() {
+        User aUser = new User();
+
+            assertWithMessage("TEST-985: Secret user subject was NOT null!").that(aUser)
+                .named("User [%s]", aUser.getName())
+                .isNull();
+    }
+
+    private Table<String, String, String> getDummyGuavaTable() {
+        Table<String, String, String> aTable = TreeBasedTable.create();
+        aTable.put("firstRow", "firstColumn", "baeldung");
+        return aTable;
+    }
+
+    // Custom User type
+    @Test
+    public void whenCheckingUser_thenHasName() {
+        User aUser = new User();
+
+        assertThat(aUser).hasName("John Doe");
+    }
+
+    @Test
+    public void whenCheckingUser_thenHasNameIgnoringCase() {
+        User aUser = new User();
+
+        assertThat(aUser).hasNameIgnoringCase("john doe");
+    }
+
+    @Test
+    public void givenUser_whenCheckingEmails_thenExpectedSize() {
+        User aUser = new User();
+
+        assertThat(aUser).emails()
+            .hasSize(2);
+    }
+
+}

testing-modules/easy-random/README.md

@@ -0,0 +1,3 @@
+## Relevant Articles:
+
+- [Quick Guide to EasyRandom in Java](https://www.baeldung.com/java-easy-random)

testing-modules/easy-random/pom.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>easy-random</artifactId>
+    <name>easy-random</name>
+
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jeasy</groupId>
+            <artifactId>easy-random-core</artifactId>
+            <version>${easy-random-core.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <easy-random-core.version>4.0.0</easy-random-core.version>
+    </properties>
+
+</project>

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/model/Department.java

@@ -0,0 +1,17 @@
+package org.baeldung.easy.random.model;
+
+import java.util.StringJoiner;
+
+public class Department {
+    private String depName;
+
+    public Department(String depName) {
+        this.depName = depName;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Department.class.getSimpleName() + "[", "]").add("depName='" + depName + "'")
+            .toString();
+    }
+}

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/model/Employee.java

@@ -0,0 +1,70 @@
+package org.baeldung.easy.random.model;
+
+import java.util.*;
+
+public class Employee {
+
+    private long id;
+    private String firstName;
+    private String lastName;
+    private Department department;
+    private Collection<Employee> coworkers;
+    private Map<YearQuarter, Grade> quarterGrades;
+
+    public Employee(long id, String firstName, String lastName, Department department) {
+        this.id = id;
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.department = department;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        Employee employee = (Employee) o;
+        return id == employee.id;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public Department getDepartment() {
+        return department;
+    }
+
+    public Collection<Employee> getCoworkers() {
+        return Collections.unmodifiableCollection(coworkers);
+    }
+
+    public Map<YearQuarter, Grade> getQuarterGrades() {
+        return Collections.unmodifiableMap(quarterGrades);
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Employee.class.getSimpleName() + "[", "]").add("id=" + id)
+            .add("firstName='" + firstName + "'")
+            .add("lastName='" + lastName + "'")
+            .add("department=" + department)
+            .add("coworkers size=" + ((coworkers == null) ? 0 : coworkers.size()))
+            .add("quarterGrades=" + quarterGrades)
+            .toString();
+    }
+}

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/model/Grade.java

@@ -0,0 +1,22 @@
+package org.baeldung.easy.random.model;
+
+import java.util.StringJoiner;
+
+public class Grade {
+
+    private int grade;
+
+    public Grade(int grade) {
+        this.grade = grade;
+    }
+
+    public int getGrade() {
+        return grade;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Grade.class.getSimpleName() + "[", "]").add("grade=" + grade)
+            .toString();
+    }
+}

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/model/Person.java

@@ -0,0 +1,30 @@
+package org.baeldung.easy.random.model;
+
+import java.util.StringJoiner;
+
+public class Person {
+
+    private String firstName;
+    private String lastName;
+    private Integer age;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Person.class.getSimpleName() + "[", "]").add("firstName='" + firstName + "'")
+            .add("lastName='" + lastName + "'")
+            .add("age=" + age)
+            .toString();
+    }
+}

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/model/YearQuarter.java

@@ -0,0 +1,50 @@
+package org.baeldung.easy.random.model;
+
+import java.time.LocalDate;
+import java.util.Objects;
+import java.util.StringJoiner;
+
+public class YearQuarter {
+
+    private LocalDate startDate;
+    private LocalDate endDate;
+
+    public YearQuarter(LocalDate startDate) {
+        this.startDate = startDate;
+        autoAdjustEndDate();
+    }
+
+    private void autoAdjustEndDate() {
+        endDate = startDate.plusMonths(3L);
+    }
+
+    public LocalDate getStartDate() {
+        return startDate;
+    }
+
+    public LocalDate getEndDate() {
+        return endDate;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        YearQuarter quarter = (YearQuarter) o;
+        return Objects.equals(startDate, quarter.startDate) && Objects.equals(endDate, quarter.endDate);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(startDate, endDate);
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", YearQuarter.class.getSimpleName() + "[", "]").add("startDate=" + startDate)
+            .add("endDate=" + endDate)
+            .toString();
+    }
+}

testing-modules/easy-random/src/main/java/org/baeldung/easy/random/randomizer/YearQuarterRandomizer.java

@@ -0,0 +1,18 @@
+package org.baeldung.easy.random.randomizer;
+
+import org.baeldung.easy.random.model.YearQuarter;
+import org.jeasy.random.api.Randomizer;
+
+import java.time.LocalDate;
+import java.time.Month;
+
+public class YearQuarterRandomizer implements Randomizer<YearQuarter> {
+
+    private LocalDate date = LocalDate.of(1990, Month.SEPTEMBER, 25);
+
+    @Override
+    public YearQuarter getRandomValue() {
+        date = date.plusMonths(3);
+        return new YearQuarter(date);
+    }
+}

testing-modules/easy-random/src/test/java/org/baeldung/easy/random/EasyRandomUnitTest.java

@@ -0,0 +1,63 @@
+package org.baeldung.easy.random;
+
+import org.baeldung.easy.random.model.Employee;
+import org.baeldung.easy.random.model.Person;
+import org.baeldung.easy.random.model.YearQuarter;
+import org.baeldung.easy.random.randomizer.YearQuarterRandomizer;
+import org.jeasy.random.EasyRandom;
+import org.jeasy.random.EasyRandomParameters;
+import org.jeasy.random.FieldPredicates;
+import org.jeasy.random.TypePredicates;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class EasyRandomUnitTest {
+
+    @Test
+    void givenDefaultConfiguration_thenGenerateSingleObject() {
+        EasyRandom generator = new EasyRandom();
+        Person person = generator.nextObject(Person.class);
+
+        assertNotNull(person.getAge());
+        assertNotNull(person.getFirstName());
+        assertNotNull(person.getLastName());
+    }
+
+    @Test
+    void givenDefaultConfiguration_thenGenerateObjectsList() {
+        EasyRandom generator = new EasyRandom();
+        List<Person> persons = generator.objects(Person.class, 5)
+            .collect(Collectors.toList());
+
+        assertEquals(5, persons.size());
+    }
+
+    @Test
+    void givenCustomConfiguration_thenGenerateSingleEmployee() {
+        EasyRandomParameters parameters = new EasyRandomParameters();
+        parameters.stringLengthRange(3, 3);
+        parameters.collectionSizeRange(5, 5);
+        parameters.excludeField(FieldPredicates.named("lastName").and(FieldPredicates.inClass(Employee.class)));
+        parameters.excludeType(TypePredicates.inPackage("not.existing.pkg"));
+        parameters.randomize(YearQuarter.class, new YearQuarterRandomizer());
+
+        EasyRandom generator = new EasyRandom(parameters);
+        Employee employee = generator.nextObject(Employee.class);
+
+        assertEquals(3, employee.getFirstName().length());
+        assertEquals(5, employee.getCoworkers().size());
+        assertEquals(5, employee.getQuarterGrades().size());
+        assertNotNull(employee.getDepartment());
+
+        assertNull(employee.getLastName());
+
+        for (YearQuarter key : employee.getQuarterGrades().keySet()) {
+            assertEquals(key.getStartDate(), key.getEndDate().minusMonths(3L));
+        }
+    }
+
+}

testing-modules/easymock/README.md

@@ -0,0 +1,3 @@
+## Relevant Articles
+
+- [Mocking a Void Method with EasyMock](https://www.baeldung.com/easymock-mocking-void-method)

testing-modules/easymock/pom.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<project
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>easymock</artifactId>
+    <name>easymock</name>
+    <url>http://maven.apache.org</url>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>testing-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.easymock</groupId>
+            <artifactId>easymock</artifactId>
+            <version>${easymock.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <easymock.version>4.0.2</easymock.version>
+    </properties>
+</project>

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/ForecastProcessor.java

@@ -0,0 +1,28 @@
+package com.baeldung.testing.easymock;
+
+import java.math.BigDecimal;
+
+public class ForecastProcessor {
+    private WeatherService weatherService;
+    
+    public BigDecimal getMaximumTemperature(String locationName) {
+        
+        Location location = new Location(locationName);
+        
+        try {
+            weatherService.populateTemperature(location);
+        } catch (ServiceUnavailableException e) {
+           return null;
+        }
+        
+        return location.getMaximumTemparature();
+    }
+
+    public WeatherService getWeatherService() {
+        return weatherService;
+    }
+
+    public void setWeatherService(WeatherService weatherService) {
+        this.weatherService = weatherService;
+    }    
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/Location.java

@@ -0,0 +1,33 @@
+package com.baeldung.testing.easymock;
+
+import java.math.BigDecimal;
+
+public class Location {
+    private String name;
+    private BigDecimal minimumTemperature;
+    private BigDecimal maximumTemparature;
+    
+    public Location(String name) {
+        this.name = name;
+    }   
+    
+    public String getName() {
+        return name;
+    }
+    
+    public BigDecimal getMinimumTemperature() {
+        return minimumTemperature;
+    }
+    
+    public void setMinimumTemperature(BigDecimal minimumTemperature) {
+        this.minimumTemperature = minimumTemperature;
+    }
+    
+    public BigDecimal getMaximumTemparature() {
+        return maximumTemparature;
+    }
+    
+    public void setMaximumTemparature(BigDecimal maximumTemparature) {
+        this.maximumTemparature = maximumTemparature;
+    }
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/ServiceUnavailableException.java

@@ -0,0 +1,7 @@
+package com.baeldung.testing.easymock;
+
+public class ServiceUnavailableException extends Exception {
+
+    private static final long serialVersionUID = 6961151537340723535L;
+
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/WeatherService.java

@@ -0,0 +1,5 @@
+package com.baeldung.testing.easymock;
+
+public interface WeatherService {
+    void populateTemperature(Location location) throws ServiceUnavailableException;
+}

testing-modules/easymock/src/test/java/com/baeldung/testing/easymock/ForecastProcessorUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.testing.easymock;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+import java.math.BigDecimal;
+
+import org.easymock.EasyMock;
+import org.easymock.EasyMockRule;
+import org.easymock.Mock;
+import org.easymock.TestSubject;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class ForecastProcessorUnitTest {
+    private static int MAX_TEMP = 90;
+    
+    @Rule
+    public EasyMockRule rule = new EasyMockRule(this);
+
+    @TestSubject
+    private ForecastProcessor forecastProcessor = new ForecastProcessor();
+
+    @Mock
+    private WeatherService mockWeatherService;
+
+    @Before
+    public void setUp() {
+        forecastProcessor.setWeatherService(mockWeatherService);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void givenLocationName_whenWeatherServicePopulatesTemperatures_thenMaxTempReturned() throws ServiceUnavailableException {
+        mockWeatherService.populateTemperature(EasyMock.anyObject(Location.class));
+        EasyMock.expectLastCall()
+            .andAnswer(() -> {
+                Location passedLocation = (Location) EasyMock.getCurrentArguments()[0]; 
+                passedLocation.setMaximumTemparature(new BigDecimal(MAX_TEMP)); 
+                passedLocation.setMinimumTemperature(new BigDecimal(MAX_TEMP - 10));
+                return null;
+            });
+        EasyMock.replay(mockWeatherService);
+        BigDecimal maxTemperature = forecastProcessor.getMaximumTemperature("New York");
+        EasyMock.verify(mockWeatherService);
+        assertThat(maxTemperature, equalTo(new BigDecimal(MAX_TEMP)));
+    }
+}

testing-modules/gatling/README.md

@@ -0,0 +1,5 @@
+### Relevant Articles:
+- [Intro to Gatling](http://www.baeldung.com/introduction-to-gatling)
+
+### Running a simualtion
+- To run a simulation use "simulation" profile, command - `mvn install -Psimulation -Dgib.enabled=false`

testing-modules/gatling/pom.xml

@@ -0,0 +1,136 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.baeldung</groupId>
+	<artifactId>gatling</artifactId>
+	<version>1.0-SNAPSHOT</version>
+	<name>gatling</name>
+	
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>io.gatling</groupId>
+				<artifactId>gatling-app</artifactId>
+				<version>${gatling.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.gatling</groupId>
+				<artifactId>gatling-recorder</artifactId>
+				<version>${gatling.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.gatling.highcharts</groupId>
+				<artifactId>gatling-charts-highcharts</artifactId>
+				<version>${gatling.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>org.scala-lang</groupId>
+				<artifactId>scala-library</artifactId>
+				<version>${scala.version}</version>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+    
+	<dependencies>
+		<dependency>
+			<groupId>io.gatling.highcharts</groupId>
+			<artifactId>gatling-charts-highcharts</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>io.gatling</groupId>
+			<artifactId>gatling-app</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>io.gatling</groupId>
+			<artifactId>gatling-recorder</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.scala-lang</groupId>
+			<artifactId>scala-library</artifactId>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<testSourceDirectory>src/test/scala</testSourceDirectory>
+		<pluginManagement>
+			<plugins>
+				<plugin>
+					<groupId>net.alchim31.maven</groupId>
+					<artifactId>scala-maven-plugin</artifactId>
+					<version>${scala-maven-plugin.version}</version>
+				</plugin>
+			</plugins>
+		</pluginManagement>
+		<plugins>
+			<plugin>
+				<groupId>net.alchim31.maven</groupId>
+				<artifactId>scala-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<goals>
+							<goal>testCompile</goal>
+						</goals>
+						<configuration>
+							<args>
+								<!--<arg>-Ybackend:GenBCode</arg> -->
+								<arg>-Ydelambdafy:method</arg>
+								<arg>-target:jvm-1.8</arg>
+								<arg>-deprecation</arg>
+								<arg>-feature</arg>
+								<arg>-unchecked</arg>
+								<arg>-language:implicitConversions</arg>
+								<arg>-language:postfixOps</arg>
+							</args>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+	
+	<profiles>
+		<profile>
+			<id>simulation</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>io.gatling</groupId>
+						<artifactId>gatling-maven-plugin</artifactId>
+						<version>${gatling-maven-plugin.version}</version>
+						<executions>
+							<execution>
+								<phase>test</phase>
+								<goals>
+									<goal>execute</goal>
+								</goals>
+								<configuration>
+									<disableCompiler>true</disableCompiler>
+								</configuration>
+							</execution>
+						</executions>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
+	</profiles>
+
+	<properties>
+		<maven.compiler.source>1.8</maven.compiler.source>
+		<maven.compiler.target>1.8</maven.compiler.target>
+		<encoding>UTF-8</encoding>
+		<scala.version>2.12.6</scala.version> <!--2.11.12 --> <!--2.12.6 -->
+		<gatling.version>2.3.1</gatling.version> <!--2.2.5 --> <!--2.3.1 -->
+		<scala-maven-plugin.version>3.2.2</scala-maven-plugin.version> <!--3.2.2 --> <!--3.3.2 -->
+		<gatling-maven-plugin.version>2.2.4</gatling-maven-plugin.version> <!--2.2.1 --> <!--2.2.4 -->
+	</properties>
+
+</project>

testing-modules/gatling/src/test/resources/gatling.conf

@@ -0,0 +1,127 @@
+#########################
+# Gatling Configuration #
+#########################
+
+# This file contains all the settings configurable for Gatling with their default values
+
+gatling {
+  core {
+    #outputDirectoryBaseName = "" # The prefix for each simulation result folder (then suffixed by the report generation timestamp)
+    #runDescription = ""          # The description for this simulation run, displayed in each report
+    #encoding = "utf-8"           # Encoding to use throughout Gatling for file and string manipulation
+    #simulationClass = ""         # The FQCN of the simulation to run (when used in conjunction with noReports, the simulation for which assertions will be validated)
+    #mute = false                 # When set to true, don't ask for simulation name nor run description (currently only used by Gatling SBT plugin)
+    #elFileBodiesCacheMaxCapacity = 200        # Cache size for request body EL templates, set to 0 to disable
+    #rawFileBodiesCacheMaxCapacity = 200       # Cache size for request body Raw templates, set to 0 to disable
+    #rawFileBodiesInMemoryMaxSize = 1000       # Below this limit, raw file bodies will be cached in memory
+
+    extract {
+      regex {
+        #cacheMaxCapacity = 200 # Cache size for the compiled regexes, set to 0 to disable caching
+      }
+      xpath {
+        #cacheMaxCapacity = 200 # Cache size for the compiled XPath queries,  set to 0 to disable caching
+      }
+      jsonPath {
+        #cacheMaxCapacity = 200 # Cache size for the compiled jsonPath queries, set to 0 to disable caching
+        #preferJackson = false  # When set to true, prefer Jackson over Boon for JSON-related operations
+      }
+      css {
+        #cacheMaxCapacity = 200 # Cache size for the compiled CSS selectors queries,  set to 0 to disable caching
+      }
+    }
+
+    directory {
+      #data = user-files/data               # Folder where user's data (e.g. files used by Feeders) is located
+      #bodies = user-files/bodies           # Folder where bodies are located
+      #simulations = user-files/simulations # Folder where the bundle's simulations are located
+      #reportsOnly = ""                     # If set, name of report folder to look for in order to generate its report
+      #binaries = ""                        # If set, name of the folder where compiles classes are located: Defaults to GATLING_HOME/target.
+      #results = results                    # Name of the folder where all reports folder are located
+    }
+  }
+  charting {
+    #noReports = false       # When set to true, don't generate HTML reports
+    #maxPlotPerSeries = 1000 # Number of points per graph in Gatling reports
+    #useGroupDurationMetric = false  # Switch group timings from cumulated response time to group duration.
+    indicators {
+      #lowerBound = 800      # Lower bound for the requests' response time to track in the reports and the console summary
+      #higherBound = 1200    # Higher bound for the requests' response time to track in the reports and the console summary
+      #percentile1 = 50      # Value for the 1st percentile to track in the reports, the console summary and Graphite
+      #percentile2 = 75      # Value for the 2nd percentile to track in the reports, the console summary and Graphite
+      #percentile3 = 95      # Value for the 3rd percentile to track in the reports, the console summary and Graphite
+      #percentile4 = 99      # Value for the 4th percentile to track in the reports, the console summary and Graphite
+    }
+  }
+  http {
+    #fetchedCssCacheMaxCapacity = 200          # Cache size for CSS parsed content, set to 0 to disable
+    #fetchedHtmlCacheMaxCapacity = 200         # Cache size for HTML parsed content, set to 0 to disable
+    #perUserCacheMaxCapacity = 200             # Per virtual user cache size, set to 0 to disable
+    #warmUpUrl = "http://gatling.io"           # The URL to use to warm-up the HTTP stack (blank means disabled)
+    #enableGA = true                           # Very light Google Analytics, please support
+    ssl {
+      keyStore {
+        #type = ""      # Type of SSLContext's KeyManagers store
+        #file = ""      # Location of SSLContext's KeyManagers store
+        #password = ""  # Password for SSLContext's KeyManagers store
+        #algorithm = "" # Algorithm used SSLContext's KeyManagers store
+      }
+      trustStore {
+        #type = ""      # Type of SSLContext's TrustManagers store
+        #file = ""      # Location of SSLContext's TrustManagers store
+        #password = ""  # Password for SSLContext's TrustManagers store
+        #algorithm = "" # Algorithm used by SSLContext's TrustManagers store
+      }
+    }
+    ahc {
+      #keepAlive = true                                # Allow pooling HTTP connections (keep-alive header automatically added)
+      #connectTimeout = 60000                          # Timeout when establishing a connection
+      #pooledConnectionIdleTimeout = 60000             # Timeout when a connection stays unused in the pool
+      #readTimeout = 60000                             # Timeout when a used connection stays idle
+      #maxRetry = 2                                    # Number of times that a request should be tried again
+      #requestTimeout = 60000                          # Timeout of the requests
+      #acceptAnyCertificate = true                     # When set to true, doesn't validate SSL certificates
+      #httpClientCodecMaxInitialLineLength = 4096      # Maximum length of the initial line of the response (e.g. "HTTP/1.0 200 OK")
+      #httpClientCodecMaxHeaderSize = 8192             # Maximum size, in bytes, of each request's headers
+      #httpClientCodecMaxChunkSize = 8192              # Maximum length of the content or each chunk
+      #webSocketMaxFrameSize = 10240000                # Maximum frame payload size
+      #sslEnabledProtocols = [TLSv1.2, TLSv1.1, TLSv1] # Array of enabled protocols for HTTPS, if empty use the JDK defaults
+      #sslEnabledCipherSuites = []                     # Array of enabled cipher suites for HTTPS, if empty  use the JDK defaults
+      #sslSessionCacheSize = 0                         # SSLSession cache size, set to 0 to use JDK's default
+      #sslSessionTimeout = 0                           # SSLSession timeout in seconds, set to 0 to use JDK's default (24h)
+      #useOpenSsl = false                              # if OpenSSL should be used instead of JSSE (requires tcnative jar)
+      #useNativeTransport = false                      # if native transport should be used instead of Java NIO (requires netty-transport-native-epoll, currently Linux only)
+      #usePooledMemory = true                          # if Gatling should use pooled memory
+      #tcpNoDelay = true
+      #soReuseAddress = false
+      #soLinger = -1
+      #soSndBuf = -1
+      #soRcvBuf = -1
+    }
+    dns {
+      #queryTimeout = 5000                             # Timeout of each DNS query in millis
+      #maxQueriesPerResolve = 3                        # Maximum allowed number of DNS queries for a given name resolution
+    }
+  }
+  data {
+    #writers = [console, file]      # The list of DataWriters to which Gatling write simulation data (currently supported : console, file, graphite, jdbc)
+    console {
+      #light = false                # When set to true, displays a light version without detailed request stats
+    }
+    file {
+      #bufferSize = 8192            # FileDataWriter's internal data buffer size, in bytes
+    }
+    leak {
+      #noActivityTimeout = 30  # Period, in seconds, for which Gatling may have no activity before considering a leak may be happening
+    }
+    graphite {
+      #light = false              # only send the all* stats
+      #host = "localhost"         # The host where the Carbon server is located
+      #port = 2003                # The port to which the Carbon server listens to (2003 is default for plaintext, 2004 is default for pickle)
+      #protocol = "tcp"           # The protocol used to send data to Carbon (currently supported : "tcp", "udp")
+      #rootPathPrefix = "gatling" # The common prefix of all metrics sent to Graphite
+      #bufferSize = 8192          # GraphiteDataWriter's internal data buffer size, in bytes
+      #writeInterval = 1          # GraphiteDataWriter's write interval, in seconds
+    }
+  }
+}

testing-modules/gatling/src/test/resources/logback.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%-5level] %logger{15} - %msg%n%rEx</pattern>
+            <immediateFlush>false</immediateFlush>
+        </encoder>
+    </appender>
+
+    <!-- Uncomment for logging ALL HTTP request and responses -->
+    <!-- 	<logger name="io.gatling.http.ahc" level="TRACE" /> -->
+    <!--    <logger name="io.gatling.http.response" level="TRACE" /> -->
+    <!-- Uncomment for logging ONLY FAILED HTTP request and responses -->
+    <!-- 	<logger name="io.gatling.http.ahc" level="DEBUG" /> -->
+    <!--    <logger name="io.gatling.http.response" level="DEBUG" /> -->
+
+    <root level="WARN">
+        <appender-ref ref="CONSOLE" />
+    </root>
+
+</configuration>

testing-modules/gatling/src/test/resources/recorder.conf

@@ -0,0 +1,53 @@
+recorder {
+  core {
+    #mode = "Proxy"
+    #encoding = "utf-8"               # The encoding used for reading/writing request bodies and the generated simulation
+    #outputFolder = ""                # The folder where generated simulation will we written
+    #package = ""                     # The package's name of the generated simulation
+    #className = "RecordedSimulation" # The name of the generated Simulation class
+    #thresholdForPauseCreation = 100  # The minimum time, in milliseconds, that must pass between requests to trigger a pause creation
+    #saveConfig = false               # When set to true, the configuration from the Recorder GUI overwrites this configuration
+    #headless = false                 # When set to true, run the Recorder in headless mode instead of the GUI
+    #harFilePath = ""                 # The path of the HAR file to convert
+  }
+  filters {
+    #filterStrategy = "Disabled" # The selected filter resources filter strategy (currently supported : "Disabled", "BlackList", "WhiteList")
+    #whitelist = []              # The list of ressources patterns that are part of the Recorder's whitelist
+    #blacklist = []              # The list of ressources patterns that are part of the Recorder's blacklist
+  }
+  http {
+    #automaticReferer = true       # When set to false, write the referer + enable 'disableAutoReferer' in the generated simulation
+    #followRedirect = true         # When set to false, write redirect requests + enable 'disableFollowRedirect' in the generated simulation
+    #removeCacheHeaders = true     # When set to true, removes from the generated requests headers leading to request caching
+    #inferHtmlResources = true     # When set to true, add inferred resources + set 'inferHtmlResources' with the configured blacklist/whitelist in the generated simulation
+    #checkResponseBodies = false   # When set to true, save response bodies as files and add raw checks in the generated simulation
+  }
+  proxy {
+    #port = 8000                         # Local port used by Gatling's Proxy for HTTP/HTTPS
+    https {
+      #mode = "SelfSignedCertificate"    # The selected "HTTPS mode" (currently supported : "SelfSignedCertificate", "ProvidedKeyStore", "GatlingCertificateAuthority", "CustomCertificateAuthority")
+      keyStore {
+        #path = ""                       # The path of the custom key store
+        #password = ""                   # The password for this key store
+        #type = "JKS"                    # The type of the key store (currently supported: "JKS")
+      }
+      certificateAuthority {
+        #certificatePath = ""            # The path of the custom certificate
+        #privateKeyPath = ""             # The certificate's private key path
+      }
+    }
+    outgoing {
+      #host = ""     # The outgoing proxy's hostname
+      #username = "" # The username to use to connect to the outgoing proxy
+      #password = "" # The password corresponding to the user to use to connect to the outgoing proxy
+      #port = 0      # The HTTP port to use to connect to the outgoing proxy
+      #sslPort = 0   # If set, The HTTPS port to use to connect to the outgoing proxy
+    }
+  }
+  netty {
+    #maxInitialLineLength = 10000 # Maximum length of the initial line of the response (e.g. "HTTP/1.0 200 OK")
+    #maxHeaderSize = 20000        # Maximum size, in bytes, of each request's headers
+    #maxChunkSize = 8192          # Maximum length of the content or each chunk
+    #maxContentLength = 100000000 # Maximum length of the aggregated content of each response
+  }
+}

testing-modules/gatling/src/test/scala/Engine.scala

@@ -0,0 +1,13 @@
+import io.gatling.app.Gatling
+import io.gatling.core.config.GatlingPropertiesBuilder
+
+object Engine extends App {
+
+    val props = new GatlingPropertiesBuilder
+    props.dataDirectory(IDEPathHelper.dataDirectory.toString)
+    props.resultsDirectory(IDEPathHelper.resultsDirectory.toString)
+    props.bodiesDirectory(IDEPathHelper.bodiesDirectory.toString)
+    props.binariesDirectory(IDEPathHelper.mavenBinariesDirectory.toString)
+
+    Gatling.fromMap(props.build)
+}

testing-modules/gatling/src/test/scala/IDEPathHelper.scala

@@ -0,0 +1,22 @@
+import java.nio.file.Path
+
+import io.gatling.commons.util.PathHelper._
+
+object IDEPathHelper {
+
+    val gatlingConfUrl: Path = getClass.getClassLoader.getResource("gatling.conf").toURI
+    val projectRootDir = gatlingConfUrl.ancestor(3)
+
+    val mavenSourcesDirectory = projectRootDir / "src" / "test" / "scala"
+    val mavenResourcesDirectory = projectRootDir / "src" / "test" / "resources"
+    val mavenTargetDirectory = projectRootDir / "target"
+    val mavenBinariesDirectory = mavenTargetDirectory / "test-classes"
+
+    val dataDirectory = mavenResourcesDirectory / "data"
+    val bodiesDirectory = mavenResourcesDirectory / "bodies"
+
+    val recorderOutputDirectory = mavenSourcesDirectory
+    val resultsDirectory = mavenTargetDirectory / "gatling"
+
+    val recorderConfigFile = mavenResourcesDirectory / "recorder.conf"
+}

testing-modules/gatling/src/test/scala/Recorder.scala

@@ -0,0 +1,12 @@
+import io.gatling.recorder.GatlingRecorder
+import io.gatling.recorder.config.RecorderPropertiesBuilder
+
+object Recorder extends App {
+
+    val props = new RecorderPropertiesBuilder
+    props.simulationOutputFolder(IDEPathHelper.recorderOutputDirectory.toString)
+    props.simulationPackage("org.baeldung")
+    props.bodiesFolder(IDEPathHelper.bodiesDirectory.toString)
+
+    GatlingRecorder.fromMap(props.build, Some(IDEPathHelper.recorderConfigFile))
+}

testing-modules/gatling/src/test/scala/org/baeldung/RecordedSimulation.scala

@@ -0,0 +1,45 @@
+package org.baeldung
+
+import scala.concurrent.duration._
+
+import io.gatling.core.Predef._
+import io.gatling.http.Predef._
+import io.gatling.jdbc.Predef._
+
+class RecordedSimulation extends Simulation {
+
+    val httpProtocol = http
+        .baseURL("http://computer-database.gatling.io")
+        .inferHtmlResources(BlackList(""".*\.css""", """.*\.js""", """.*\.ico"""), WhiteList())
+        .acceptHeader("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+        .acceptEncodingHeader("gzip, deflate")
+        .acceptLanguageHeader("it-IT,it;q=0.8,en-US;q=0.5,en;q=0.3")
+        .userAgentHeader("Mozilla/5.0 (Windows NT 10.0; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0")
+
+
+
+
+    val scn = scenario("RecordedSimulation")
+        .exec(http("request_0")
+            .get("/"))
+        .pause(5)
+        .exec(http("request_1")
+            .get("/computers?f=amstrad"))
+        .pause(4)
+        .exec(http("request_2")
+            .get("/computers/412"))
+        .pause(2)
+        .exec(http("request_3")
+            .get("/"))
+        .pause(2)
+        .exec(http("request_4")
+            .get("/computers?p=1"))
+        .pause(1)
+        .exec(http("request_5")
+            .get("/computers?p=2"))
+        .pause(2)
+        .exec(http("request_6")
+            .get("/computers?p=3"))
+
+    setUp(scn.inject(atOnceUsers(1))).protocols(httpProtocol)
+}

testing-modules/groovy-spock/.gitignore

@@ -0,0 +1 @@
+/report-*.json

testing-modules/groovy-spock/README.md

@@ -0,0 +1,5 @@
+### Relevant articles
+
+- [Introduction to Testing with Spock and Groovy](http://www.baeldung.com/groovy-spock)
+- [Difference Between Stub, Mock, and Spy in the Spock Framework](https://www.baeldung.com/spock-stub-mock-spy)
+- [Guide to Spock Extensions](https://www.baeldung.com/spock-extensions)

testing-modules/groovy-spock/pom.xml

@@ -0,0 +1,56 @@
+<?xml version="1.0"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>org.spockframework</groupId>
+    <artifactId>groovy-spock</artifactId>
+    <version>1.0-SNAPSHOT</version>
+	<name>groovy-spock</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.spockframework</groupId>
+            <artifactId>spock-core</artifactId>
+            <version>${spock-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy-all</artifactId>
+            <version>${groovy-all.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.gmavenplus</groupId>
+                <artifactId>gmavenplus-plugin</artifactId>
+                <version>${gmavenplus-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>compile</goal>
+                            <goal>testCompile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <spock-core.version>1.3-groovy-2.4</spock-core.version>
+        <groovy-all.version>2.4.7</groovy-all.version>
+        <gmavenplus-plugin.version>1.5</gmavenplus-plugin.version>
+    </properties>
+
+</project>

testing-modules/groovy-spock/src/main/java/mocks/EventPublisher.java

@@ -0,0 +1,7 @@
+package mocks;
+
+public interface EventPublisher {
+
+    void publish(String addedOfferId);
+
+}

testing-modules/groovy-spock/src/main/java/mocks/ExternalItemProviderException.java

@@ -0,0 +1,5 @@
+package mocks;
+
+public class ExternalItemProviderException extends RuntimeException {
+
+}

testing-modules/groovy-spock/src/main/java/mocks/Item.java

@@ -0,0 +1,36 @@
+package mocks;
+
+import java.util.Objects;
+
+public class Item {
+    private final String id;
+    private final String name;
+
+    public Item(String id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Item item = (Item) o;
+        return Objects.equals(id, item.id) &&
+                Objects.equals(name, item.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, name);
+    }
+
+}

testing-modules/groovy-spock/src/main/java/mocks/ItemProvider.java

@@ -0,0 +1,9 @@
+package mocks;
+
+import java.util.List;
+
+public interface ItemProvider {
+
+    List<Item> getItems(List<String> itemIds);
+
+}

testing-modules/groovy-spock/src/main/java/mocks/ItemService.java

@@ -0,0 +1,37 @@
+package mocks;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class ItemService {
+    private final ItemProvider itemProvider;
+    private final EventPublisher eventPublisher;
+
+
+    public ItemService(ItemProvider itemProvider, EventPublisher eventPublisher) {
+        this.itemProvider = itemProvider;
+        this.eventPublisher = eventPublisher;
+    }
+
+    List<Item> getAllItemsSortedByName(List<String> itemIds) {
+        List<Item> items;
+        try{
+            items = itemProvider.getItems(itemIds);
+        } catch (RuntimeException ex) {
+            throw new ExternalItemProviderException();
+        }
+        return items.stream()
+                .sorted(Comparator.comparing(Item::getName))
+                .collect(Collectors.toList());
+    }
+
+    void saveItems(List<String> itemIds) {
+        List<String> notEmptyOfferIds = itemIds.stream()
+                .filter(itemId -> !itemId.isEmpty())
+                .collect(Collectors.toList());
+        // save in database
+        notEmptyOfferIds.forEach(eventPublisher::publish);
+    }
+
+}

testing-modules/groovy-spock/src/main/java/mocks/LoggingEventPublisher.java

@@ -0,0 +1,10 @@
+package mocks;
+
+public class LoggingEventPublisher implements EventPublisher {
+
+    @Override
+    public void publish(String addedOfferId) {
+        System.out.println("I've published: " + addedOfferId);
+    }
+
+}

testing-modules/groovy-spock/src/test/groovy/FirstSpecification.groovy

@@ -0,0 +1,89 @@
+import spock.lang.Specification
+
+class FirstSpecification extends Specification {
+
+    def "one plus one should equal two"() {
+        expect:
+        1 + 1 == 2
+    }
+
+    def "two plus two should equal four"() {
+        given:
+        int left = 2
+        int right = 2
+
+        when:
+        int result = left + right
+
+        then:
+        result == 4
+    }
+
+    def "Should be able to remove from list"() {
+        given:
+        def list = [1, 2, 3, 4]
+
+        when:
+        list.remove(0)
+
+        then:
+        list == [2, 3, 4]
+    }
+
+    def "Should get an index out of bounds when removing a non-existent item"() {
+        given:
+        def list = [1, 2, 3, 4]
+
+        when:
+        list.remove(20)
+
+        then:
+        thrown(IndexOutOfBoundsException)
+        list.size() == 4
+    }
+
+    def "numbers to the power of two"(int a, int b, int c) {
+        expect:
+        Math.pow(a, b) == c
+
+        where:
+        a | b | c
+        1 | 2 | 1
+        2 | 2 | 4
+        3 | 2 | 9
+    }
+
+    def "Should return default value for mock"() {
+        given:
+        def paymentGateway = Mock(PaymentGateway)
+
+        when:
+        def result = paymentGateway.makePayment(12.99)
+
+        then:
+        !result
+    }
+
+    def "Should return true value for mock"() {
+        given:
+        def paymentGateway = Mock(PaymentGateway)
+        paymentGateway.makePayment(20) >> true
+
+        when:
+        def result = paymentGateway.makePayment(20)
+
+        then:
+        result
+    }
+
+    def "Should verify notify was called"() {
+        given:
+        def notifier = Mock(Notifier)
+
+        when:
+        notifier.notify('foo')
+
+        then:
+        1 * notifier.notify('foo')
+    }
+}

testing-modules/groovy-spock/src/test/groovy/Notifier.groovy

@@ -0,0 +1,3 @@
+interface Notifier {
+    void notify(String message)
+}

testing-modules/groovy-spock/src/test/groovy/PaymentGateway.groovy

@@ -0,0 +1,3 @@
+interface PaymentGateway {
+    boolean makePayment(BigDecimal amount)
+}

testing-modules/groovy-spock/src/test/groovy/extensions/CustomTitleTest.groovy

@@ -0,0 +1,20 @@
+package extensions
+
+import spock.lang.Narrative
+import spock.lang.Specification
+import spock.lang.Title
+
+
+@Title("""This title is easy to read for humans""")
+class CustomTitleTest extends Specification {
+
+}
+
+@Narrative("""
+    as a user
+    i want to save favourite items 
+    and then get the list of them
+""")
+class NarrativeDescriptionTest extends Specification {
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/IgnoreIfTest.groovy

@@ -0,0 +1,22 @@
+package extensions
+
+import spock.lang.IgnoreIf
+import spock.lang.Specification
+
+
+class IgnoreIfTest extends Specification {
+
+    @IgnoreIf({System.getProperty("os.name").contains("windows")})
+    def "I won't run on windows"() {
+        expect:
+        true
+    }
+
+    @IgnoreIf({ os.isWindows() })
+    def "I'm using Spock helper classes to run only on windows"() {
+        expect:
+        true
+    }
+
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/IgnoreRestTest.groovy

@@ -0,0 +1,16 @@
+package extensions
+
+import spock.lang.IgnoreRest
+import spock.lang.Specification
+
+
+class IgnoreRestTest extends Specification {
+
+    def "I won't run"() { }
+
+    @IgnoreRest
+    def 'I will run'() { }
+
+    def "I won't run too"() { }
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/IgnoreTest.groovy

@@ -0,0 +1,20 @@
+package extensions
+
+import spock.lang.Ignore
+import spock.lang.Specification
+
+@Ignore
+class IgnoreTest extends Specification {
+
+    @Ignore
+    def "I won't be executed"() {
+        expect:
+        true
+    }
+
+    def 'Example test'() {
+        expect:
+        true
+    }
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/IssueTest.groovy

@@ -0,0 +1,25 @@
+package extensions
+
+import spock.lang.Issue
+import spock.lang.Specification
+
+
+class IssueTest extends Specification {
+
+
+    @Issue("http://jira.org/issues/LO-531")
+    def 'single issue'() {
+    }
+
+    @Issue(["http://jira.org/issues/LO-531", "http://jira.org/issues/LO-123"])
+    def 'multiple issues'() {
+    }
+
+    @Issue("LO-1000")
+    def "I'm using Spock configuration file"() {
+        expect:
+        true
+    }
+
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/PendingFeatureTest.groovy

@@ -0,0 +1,11 @@
+package extensions
+
+import spock.lang.PendingFeature
+
+class PendingFeatureTest {
+
+    @PendingFeature
+    def 'test for not implemented yet feature'() {
+
+    }
+}

testing-modules/groovy-spock/src/test/groovy/extensions/RequiresTest.groovy

@@ -0,0 +1,14 @@
+package extensions
+
+import spock.lang.Requires
+import spock.lang.Specification
+
+
+class RequiresTest extends Specification {
+
+    @Requires({ System.getProperty("os.name").contains("windows") })
+    def "I will run only on Windows"() {
+        expect:
+        true
+    }
+}

testing-modules/groovy-spock/src/test/groovy/extensions/RestoreSystemPropertiesTest.groovy

@@ -0,0 +1,18 @@
+package extensions
+
+import spock.lang.Specification
+import spock.util.environment.RestoreSystemProperties
+
+
+class RestoreSystemPropertiesTest extends Specification {
+
+    @RestoreSystemProperties
+    def 'all environment variables will be saved before execution and restored after tests'() {
+        given:
+        System.setProperty('os.name', 'Mac OS')
+
+        expect:
+        true
+    }
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/RetryTest.groovy

@@ -0,0 +1,20 @@
+package extensions
+
+import spock.lang.Retry
+import spock.lang.Specification
+
+@Retry
+class RetryTest extends Specification {
+
+    @Retry
+    def 'I will retry three times'() { }
+
+    @Retry(exceptions = [RuntimeException])
+    def 'I will retry only on RuntimeException'() { }
+
+    @Retry(condition = { failure.message.contains('error') })
+    def 'I will retry with a specific message'() { }
+
+    @Retry(delay = 1000)
+    def 'I will retry after 1000 millis'() { }
+}

testing-modules/groovy-spock/src/test/groovy/extensions/SeeTest.groovy

@@ -0,0 +1,20 @@
+package extensions
+
+import spock.lang.See
+import spock.lang.Specification
+
+
+class SeeTest extends Specification {
+
+
+    @See("https://example.org")
+    def 'Look at the reference'() {
+
+    }
+
+    @See(["https://example.org/first", "https://example.org/first"])
+    def 'Look at the references'() {
+
+    }
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/StackTraceTest.groovy

@@ -0,0 +1,13 @@
+package extensions
+
+import org.junit.Ignore
+import spock.lang.Specification
+
+
+class StackTraceTest extends Specification {
+
+    def 'stkacktrace'() {
+//        expect:
+//        throw new RuntimeException("blabla")
+    }
+}

testing-modules/groovy-spock/src/test/groovy/extensions/StepwiseTest.groovy

@@ -0,0 +1,14 @@
+package extensions
+
+import spock.lang.Specification
+import spock.lang.Stepwise
+
+
+@Stepwise
+class StepwiseTest extends Specification {
+
+    def 'I will run as first'() { }
+
+    def 'I will run as second'() { }
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/SubjectTest.groovy

@@ -0,0 +1,13 @@
+package extensions
+
+import mocks.ItemService
+import spock.lang.Specification
+import spock.lang.Subject
+
+
+class SubjectTest extends Specification {
+
+    @Subject
+    ItemService itemService // initialization here...
+
+}

testing-modules/groovy-spock/src/test/groovy/extensions/TimeoutTest.groovy

@@ -0,0 +1,24 @@
+package extensions
+
+import spock.lang.Specification
+import spock.lang.Timeout
+
+import java.util.concurrent.TimeUnit
+
+@Timeout(5)
+class TimeoutTest extends Specification {
+
+    @Timeout(1)
+    def 'I have one second to finish'() {
+
+    }
+
+    def 'I will have 5 seconds timeout'() {}
+
+    @Timeout(value = 200, unit = TimeUnit.SECONDS)
+    def 'I will fail after 200 millis'() {
+        expect:
+        true
+    }
+
+}

testing-modules/groovy-spock/src/test/groovy/mocks/ItemServiceUnitTest.groovy

@@ -0,0 +1,131 @@
+package mocks
+
+import spock.lang.Specification
+
+class ItemServiceUnitTest extends Specification {
+
+    ItemProvider itemProvider
+    ItemService itemService
+    EventPublisher eventPublisher
+
+    def setup() {
+        itemProvider = Stub(ItemProvider)
+        eventPublisher = Mock(EventPublisher)
+        itemService = new ItemService(itemProvider, eventPublisher)
+    }
+
+    def 'should return items sorted by name'() {
+        given:
+        def ids = ['offer-id', 'offer-id-2']
+        itemProvider.getItems(ids) >> [new Item('offer-id-2', 'Zname'), new Item('offer-id', 'Aname')]
+
+        when:
+        List<Item> items = itemService.getAllItemsSortedByName(ids)
+
+        then:
+        items.collect { it.name } == ['Aname', 'Zname']
+    }
+
+    def 'arguments constraints'() {
+        itemProvider.getItems(['offer-id'])
+        itemProvider.getItems(_) >> []
+        itemProvider.getItems(*_) >> []
+        itemProvider.getItems(!null) >> []
+        itemProvider.getItems({ it.size > 0 }) >> []
+    }
+
+    def 'should return different items on subsequent call'() {
+        given:
+        itemProvider.getItems(_) >>> [
+                [],
+                [new Item('1', 'name')],
+                [new Item('2', 'name')]
+        ]
+
+        when: 'method is called for the first time'
+        List<Item> items = itemService.getAllItemsSortedByName(['not-important'])
+
+        then: 'empty list is returned'
+        items == []
+
+        when: 'method is called for the second time'
+        items = itemService.getAllItemsSortedByName(['not-important'])
+
+        then: 'item with id=1 is returned'
+        items == [new Item('1', 'name')]
+
+        when: 'method is called for the thirdtime'
+        items = itemService.getAllItemsSortedByName(['not-important'])
+
+        then: 'item with id=2 is returned'
+        items == [new Item('2', 'name')]
+    }
+
+    def 'should throw ExternalItemProviderException when ItemProvider fails'() {
+        given:
+        itemProvider.getItems(_) >> { new RuntimeException()}
+
+        when:
+        itemService.getAllItemsSortedByName([])
+
+        then:
+        thrown(ExternalItemProviderException)
+    }
+
+    def 'chaining response'() {
+        itemProvider.getItems(_) >>> { new RuntimeException() } >> new SocketTimeoutException() >> [new Item('id', 'name')]
+    }
+
+    def 'should return different items for different ids lists'() {
+        given:
+        def firstIds = ['first']
+        def secondIds = ['second']
+        itemProvider.getItems(firstIds) >> [new Item('first', 'Zname')]
+        itemProvider.getItems(secondIds) >> [new Item('second', 'Aname')]
+
+        when:
+        def firstItems = itemService.getAllItemsSortedByName(firstIds)
+        def secondItems = itemService.getAllItemsSortedByName(secondIds)
+
+        then:
+        firstItems.first().name == 'Zname'
+        secondItems.first().name == 'Aname'
+    }
+
+    def 'should publish events about new non-empty saved offers'() {
+        given:
+        def offerIds = ['', 'a', 'b']
+
+        when:
+        itemService.saveItems(offerIds)
+
+        then:
+        2 * eventPublisher.publish({ it != null && !it.isEmpty()})
+    }
+
+    def 'should return items'() {
+        given:
+        itemProvider = Mock(ItemProvider)
+        itemProvider.getItems(['item-id']) >> [new Item('item-id', 'name')]
+        itemService = new ItemService(itemProvider, eventPublisher)
+
+        when:
+        def items = itemService.getAllItemsSortedByName(['item-id'])
+
+        then:
+        items == [new Item('item-id', 'name')]
+    }
+
+    def 'should spy on EventPublisher method call'() {
+        given:
+        LoggingEventPublisher eventPublisher = Spy(LoggingEventPublisher)
+        itemService = new ItemService(itemProvider, eventPublisher)
+
+        when:
+        itemService.saveItems(['item-id'])
+
+        then:
+        1 * eventPublisher.publish('item-id')
+    }
+
+}

testing-modules/groovy-spock/src/test/resources/SpockConfig.groovy

@@ -0,0 +1,30 @@
+import extensions.TimeoutTest
+import spock.lang.Issue
+
+runner {
+
+    if (System.getenv("FILTER_STACKTRACE") == null) {
+        filterStackTrace false
+    }
+
+    report {
+        issueNamePrefix 'Bug '
+        issueUrlPrefix 'http://jira.org/issues/'
+    }
+
+    optimizeRunOrder true
+
+//    exclude TimeoutTest
+//    exclude {
+//        baseClass TimeoutTest
+//        annotation Issue
+//    }
+
+    report {
+        enabled true
+        logFileDir '.'
+        logFileName 'report.json'
+        logFileSuffix new Date().format('yyyy-MM-dd')
+    }
+
+}

testing-modules/hamcrest/README.md

@@ -0,0 +1,12 @@
+## Hamcrest
+
+This module contains articles about Hamcrest
+
+### Relevant articles
+- [Hamcrest Text Matchers](https://www.baeldung.com/hamcrest-text-matchers)
+- [Hamcrest File Matchers](https://www.baeldung.com/hamcrest-file-matchers)
+- [Hamcrest Object Matchers](https://www.baeldung.com/hamcrest-object-matchers)
+- [Hamcrest Bean Matchers](https://www.baeldung.com/hamcrest-bean-matchers)
+- [Hamcrest Number Matchers](https://www.baeldung.com/hamcrest-number-matchers)
+- [Hamcrest Common Core Matchers](https://www.baeldung.com/hamcrest-core-matchers)
+- [Hamcrest Custom Matchers](https://www.baeldung.com/hamcrest-custom-matchers)

testing-modules/hamcrest/pom.xml

@@ -0,0 +1,29 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>hamcrest</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>hamcrest</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>java-hamcrest</artifactId>
+            <version>${hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <hamcrest.version>2.0.0.0</hamcrest.version>
+    </properties>
+</project>

testing-modules/hamcrest/src/main/java/com/baeldung/hamcrest/objectmatchers/City.java

@@ -0,0 +1,41 @@
+package com.baeldung.hamcrest.objectmatchers;
+
+public class City extends Location {
+    String name;
+    String state;
+
+    public City(String name, String state) {
+        this.name = name;
+        this.state = state;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setState(String state) {
+        this.state = state;
+    }
+
+    public String getState() {
+        return state;
+    }
+
+    @Override
+    public String toString() {
+        if (this.name == null && this.state == null) return null;
+        StringBuilder sb = new StringBuilder();
+        sb.append("[");
+        sb.append("Name: ");
+        sb.append(this.name);
+        sb.append(", ");
+        sb.append("State: ");
+        sb.append(this.state);
+        sb.append("]");
+        return sb.toString();
+    }
+}

testing-modules/hamcrest/src/main/java/com/baeldung/hamcrest/objectmatchers/Location.java

@@ -0,0 +1,4 @@
+package com.baeldung.hamcrest.objectmatchers;
+
+public class Location {
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestBeansUnitTest.java

@@ -0,0 +1,86 @@
+package com.baeldung.hamcrest;
+
+import com.baeldung.hamcrest.objectmatchers.City;
+import org.junit.Test;
+
+import java.beans.PropertyDescriptor;
+import java.util.Arrays;
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+import static org.hamcrest.beans.PropertyUtil.getPropertyDescriptor;
+import static org.hamcrest.beans.PropertyUtil.propertyDescriptorsFor;
+
+public class HamcrestBeansUnitTest {
+
+    @Test
+    public void givenACity_whenHasProperty_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, hasProperty("name"));
+    }
+
+    @Test
+    public void givenACity_whenNotHasProperty_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, not(hasProperty("country")));
+    }
+
+    @Test
+    public void givenACity_whenHasPropertyWithValueEqualTo_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, hasProperty("name", equalTo("San Francisco")));
+    }
+
+    @Test
+    public void givenACity_whenHasPropertyWithValueEqualToIgnoringCase_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, hasProperty("state", equalToIgnoringCase("ca")));
+    }
+
+    @Test
+    public void givenACity_whenSamePropertyValuesAs_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+        City city2 = new City("San Francisco", "CA");
+
+        assertThat(city, samePropertyValuesAs(city2));
+    }
+
+    @Test
+    public void givenACity_whenNotSamePropertyValuesAs_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+        City city2 = new City("Los Angeles", "CA");
+
+        assertThat(city, not(samePropertyValuesAs(city2)));
+    }
+
+    @Test
+    public void givenACity_whenGetPropertyDescriptor_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+        PropertyDescriptor descriptor = getPropertyDescriptor("state", city);
+
+        assertThat(descriptor
+          .getReadMethod()
+          .getName(), is(equalTo("getState")));
+    }
+
+    @Test
+    public void givenACity_whenGetPropertyDescriptorsFor_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+        PropertyDescriptor[] descriptors = propertyDescriptorsFor(city, Object.class);
+        List<String> getters = Arrays
+          .stream(descriptors)
+          .map(x -> x
+            .getReadMethod()
+            .getName())
+          .collect(toList());
+
+        assertThat(getters, containsInAnyOrder("getName", "getState"));
+    }
+
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestCoreMatchersUnitTest.java

@@ -0,0 +1,256 @@
+package com.baeldung.hamcrest;
+
+
+import com.google.common.collect.Lists;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.StringEndsWith.endsWith;
+import static org.hamcrest.core.StringStartsWith.startsWith;
+
+public class HamcrestCoreMatchersUnitTest {
+
+    @Test
+    public void givenTestInput_WhenUsingIsForMatch() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, is("hamcrest core"));
+        assertThat(testString, is(equalTo("hamcrest core")));
+    }
+
+    @Test
+    public void givenDifferentStaticTypeTestInput_WhenUsingEqualToObject_ThenCorrect() {
+
+        // GIVEN
+        Object original = 100;
+
+        // ASSERT
+        assertThat(original, equalToObject(100));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingInstanceOfForClassTypeCheck() {
+
+        assertThat("hamcrest", is(instanceOf(String.class)));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingIsA_ThenAssertType() {
+
+        assertThat("hamcrest core", isA(String.class));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingEqualToMatcherForEquality() {
+
+        // GIVEN
+        String actualString = "Hamcrest Core";
+        List<String> actualList = Lists.newArrayList("hamcrest", "core");
+
+        // ASSERT
+        assertThat(actualString, is(equalTo("Hamcrest Core")));
+        assertThat(actualList, is(equalTo(Lists.newArrayList("hamcrest", "core"))));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingNotForMatch() {
+
+        // GIVEN
+        String testString = "hamcrest";
+
+        // ASSERT
+        assertThat(testString, not("hamcrest core"));
+        assertThat(testString, is(not(equalTo("hamcrest core"))));
+        assertThat(testString, is(not(instanceOf(Integer.class))));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingNullValueForNullCheck() {
+
+        // GIVEN
+        Integer nullObject = null;
+
+        // ASSERT
+        assertThat(nullObject, is(nullValue()));
+        assertThat(nullObject, is(nullValue(Integer.class)));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingNotNullValueForNotNullCheck() {
+
+        // GIVEN
+        Integer testNumber = 123;
+
+        // ASSERT
+        assertThat(testNumber, is(notNullValue()));
+        assertThat(testNumber, is(notNullValue(Integer.class)));
+    }
+
+    @Test
+    public void givenString_WhenStartsWith_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, startsWith("hamcrest"));
+    }
+
+    @Test
+    public void giveString_WhenStartsWithIgnoringCase_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, startsWithIgnoringCase("HAMCREST"));
+    }
+
+    @Test
+    public void givenString_WhenEndsWith_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, endsWith("core"));
+    }
+
+    @Test
+    public void givenString_WhenEndsWithIgnoringCase_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, endsWithIgnoringCase("CORE"));
+    }
+
+    @Test
+    public void givenString_WhenContainsString_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, containsString("co"));
+    }
+
+    @Test
+    public void givenString_WhenContainsStringIgnoringCase_ThenCorrect() {
+
+        // GIVEN
+        String testString = "hamcrest core";
+
+        // ASSERT
+        assertThat(testString, containsStringIgnoringCase("CO"));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingHasItemInCollection() {
+
+        // GIVEN
+        List<String> list = Lists.newArrayList("java", "spring", "baeldung");
+
+        // ASSERT
+        assertThat(list, hasItem("java"));
+        assertThat(list, hasItem(isA(String.class)));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingHasItemsInCollection() {
+
+        // GIVEN
+        List<String> list = Lists.newArrayList("java", "spring", "baeldung");
+
+        // ASSERT
+        assertThat(list, hasItems("java", "baeldung"));
+        assertThat(list, hasItems(isA(String.class), endsWith("ing")));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingAnyForClassType() {
+
+        assertThat("hamcrest", is(any(String.class)));
+        assertThat("hamcrest", is(any(Object.class)));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingAllOfForAllMatchers() {
+
+        // GIVEN
+        String testString = "Hamcrest Core";
+
+        // ASSERT
+        assertThat(testString, allOf(startsWith("Ham"), endsWith("ore"), containsString("Core")));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingAnyOfForAnyMatcher() {
+
+        // GIVEN
+        String testString = "Hamcrest Core";
+
+        // ASSERT
+        assertThat(testString, anyOf(startsWith("Ham"), containsString("baeldung")));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingBothForMatcher() {
+
+        // GIVEN
+        String testString = "Hamcrest Core Matchers";
+
+        // ASSERT
+        assertThat(testString, both(startsWith("Ham")).and(containsString("Core")));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingEitherForMatcher() {
+
+        // GIVEN
+        String testString = "Hamcrest Core Matchers";
+
+        // ASSERT
+        assertThat(testString, either(startsWith("Bael")).or(containsString("Core")));
+    }
+
+    @Test
+    public void givenTestInput_WhenUsingEveryItemForMatchInCollection() {
+
+        // GIVEN
+        List<String> testItems = Lists.newArrayList("Common", "Core", "Combinable");
+
+        // ASSERT
+        assertThat(testItems, everyItem(startsWith("Co")));
+    }
+
+    @Test
+    public void givenTwoTestInputs_WhenUsingSameInstanceForMatch() {
+
+        // GIVEN
+        String string1 = "hamcrest";
+        String string2 = string1;
+
+        // ASSERT
+        assertThat(string1, is(sameInstance(string2)));
+    }
+
+    @Test
+    public void givenTwoTestInputs_WhenUsingTheInstanceForMatch() {
+        // GIVEN
+        String string1 = "hamcrest";
+        String string2 = string1;
+
+        // ASSERT
+        assertThat(string1, is(theInstance(string2)));
+    }
+
+}
+

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestFileUnitTest.java

@@ -0,0 +1,55 @@
+package com.baeldung.hamcrest;
+
+import org.junit.Test;
+
+import java.io.File;
+
+import static org.hamcrest.io.FileMatchers.*;
+import static org.hamcrest.number.OrderingComparison.greaterThan;
+import static org.hamcrest.text.IsEqualIgnoringCase.equalToIgnoringCase;
+import static org.junit.Assert.assertThat;
+
+public class HamcrestFileUnitTest {
+
+    @Test
+    public final void whenVerifyingFileName_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aFileNamed(equalToIgnoringCase("test1.in")));
+    }
+
+    @Test
+    public final void whenVerifyingFileOrDirExist_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+        File dir = new File("src/test/resources");
+        
+        assertThat(file, anExistingFile());
+        assertThat(dir, anExistingDirectory());
+        assertThat(file, anExistingFileOrDirectory());
+        assertThat(dir, anExistingFileOrDirectory());
+    }
+
+    @Test
+    public final void whenVerifyingFileIsReadableAndWritable_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aReadableFile());
+        assertThat(file, aWritableFile());        
+    }
+
+    @Test
+    public final void whenVerifyingFileSize_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aFileWithSize(11));
+        assertThat(file, aFileWithSize(greaterThan(1L)));;
+    }
+
+    /*@Test
+    public final void whenVerifyingFilePath_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+        
+        assertThat(file, aFileWithCanonicalPath(containsString("src/test/resources")));
+        assertThat(file, aFileWithAbsolutePath(containsString("src/test/resources")));
+    }*/
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestNumberUnitTest.java

@@ -0,0 +1,170 @@
+package com.baeldung.hamcrest;
+
+import org.junit.Test;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+public class HamcrestNumberUnitTest {
+
+    @Test
+    public void givenADouble_whenCloseTo_thenCorrect() {
+        double actual = 1.3;
+        double operand = 1;
+        double error = 0.5;
+        assertThat(actual, is(closeTo(operand, error)));
+    }
+
+    @Test
+    public void givenADouble_whenNotCloseTo_thenCorrect() {
+        double actual = 1.6;
+        double operand = 1;
+        double error = 0.5;
+        assertThat(actual, is(not(closeTo(operand, error))));
+    }
+
+    @Test
+    public void givenABigDecimal_whenCloseTo_thenCorrect() {
+        BigDecimal actual = new BigDecimal("1.0003");
+        BigDecimal operand = new BigDecimal("1");
+        BigDecimal error = new BigDecimal("0.0005");
+        assertThat(actual, is(closeTo(operand, error)));
+    }
+
+    @Test
+    public void givenABigDecimal_whenNotCloseTo_thenCorrect() {
+        BigDecimal actual = new BigDecimal("1.0006");
+        BigDecimal operand = new BigDecimal("1");
+        BigDecimal error = new BigDecimal("0.0005");
+        assertThat(actual, is(not(closeTo(operand, error))));
+    }
+
+    @Test
+    public void given5_whenComparesEqualTo5_thenCorrect() {
+        Integer five = 5;
+        assertThat(five, comparesEqualTo(five));
+    }
+
+    @Test
+    public void given5_whenNotComparesEqualTo7_thenCorrect() {
+        Integer seven = 7;
+        Integer five = 5;
+        assertThat(five, not(comparesEqualTo(seven)));
+    }
+
+    @Test
+    public void given7_whenGreaterThan5_thenCorrect() {
+        Integer seven = 7;
+        Integer five = 5;
+        assertThat(seven, is(greaterThan(five)));
+    }
+
+    @Test
+    public void given7_whenGreaterThanOrEqualTo5_thenCorrect() {
+        Integer seven = 7;
+        Integer five = 5;
+        assertThat(seven, is(greaterThanOrEqualTo(five)));
+    }
+
+    @Test
+    public void given5_whenGreaterThanOrEqualTo5_thenCorrect() {
+        Integer five = 5;
+        assertThat(five, is(greaterThanOrEqualTo(five)));
+    }
+
+    @Test
+    public void given3_whenLessThan5_thenCorrect() {
+        Integer three = 3;
+        Integer five = 5;
+        assertThat(three, is(lessThan(five)));
+    }
+
+    @Test
+    public void given3_whenLessThanOrEqualTo5_thenCorrect() {
+        Integer three = 3;
+        Integer five = 5;
+        assertThat(three, is(lessThanOrEqualTo(five)));
+    }
+
+    @Test
+    public void given5_whenLessThanOrEqualTo5_thenCorrect() {
+        Integer five = 5;
+        assertThat(five, is(lessThanOrEqualTo(five)));
+    }
+
+    @Test
+    public void givenBenjamin_whenGreaterThanAmanda_thenCorrect() {
+        String amanda = "Amanda";
+        String benjamin = "Benjamin";
+        assertThat(benjamin, is(greaterThan(amanda)));
+    }
+
+    @Test
+    public void givenAmanda_whenLessThanBenajmin_thenCorrect() {
+        String amanda = "Amanda";
+        String benjamin = "Benjamin";
+        assertThat(amanda, is(lessThan(benjamin)));
+    }
+
+    @Test
+    public void givenToday_whenGreaterThanYesterday_thenCorrect() {
+        LocalDate today = LocalDate.now();
+        LocalDate yesterday = today.minusDays(1);
+        assertThat(today, is(greaterThan(yesterday)));
+    }
+
+    @Test
+    public void givenToday_whenLessThanTomorrow_thenCorrect() {
+        LocalDate today = LocalDate.now();
+        LocalDate tomorrow = today.plusDays(1);
+        assertThat(today, is(lessThan(tomorrow)));
+    }
+
+    @Test
+    public void givenAmanda_whenOlderThanBenjamin_thenCorrect() {
+        Person amanda = new Person("Amanda", 20);
+        Person benjamin = new Person("Benjamin", 18);
+        assertThat(amanda, is(greaterThan(benjamin)));
+    }
+
+    @Test
+    public void givenBenjamin_whenYoungerThanAmanda_thenCorrect() {
+        Person amanda = new Person("Amanda", 20);
+        Person benjamin = new Person("Benjamin", 18);
+        assertThat(benjamin, is(lessThan(amanda)));
+    }
+
+    class Person implements Comparable<Person> {
+        String name;
+        int age;
+
+        public Person(String name, int age) {
+            this.name = name;
+            this.age = age;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public int getAge() {
+            return age;
+        }
+
+        @Override
+        public int compareTo(Person o) {
+            if (this.age == o.getAge()) return 0;
+            if (this.age > o.age) return 1;
+            else return -1;
+        }
+    }
+
+    @Test
+    public void givenNaN_whenIsNotANumber_thenCorrect() {
+        double zero = 0d;
+        assertThat(zero / zero, is(notANumber()));
+    }
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestObjectUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.hamcrest;
+
+import com.baeldung.hamcrest.objectmatchers.City;
+import com.baeldung.hamcrest.objectmatchers.Location;
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+public class HamcrestObjectUnitTest {
+
+    @Test
+    public void givenACity_whenHasToString_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, hasToString("[Name: San Francisco, State: CA]"));
+    }
+
+    @Test
+    public void givenACity_whenHasToStringEqualToIgnoringCase_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city, hasToString(equalToIgnoringCase("[NAME: SAN FRANCISCO, STATE: CA]")));
+    }
+
+    @Test
+    public void givenACity_whenHasToStringEmptyOrNullString_thenCorrect() {
+        City city = new City(null, null);
+
+        assertThat(city, hasToString(emptyOrNullString()));
+    }
+
+    @Test
+    public void givenACity_whenTypeCompatibleWithLocation_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city.getClass(), is(typeCompatibleWith(Location.class)));
+    }
+
+    @Test
+    public void givenACity_whenTypeNotCompatibleWithString_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city.getClass(), is(not(typeCompatibleWith(String.class))));
+    }
+
+    @Test
+    public void givenACity_whenTypeCompatibleWithObject_thenCorrect() {
+        City city = new City("San Francisco", "CA");
+
+        assertThat(city.getClass(), is(typeCompatibleWith(Object.class)));
+    }
+
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/HamcrestTextUnitTest.java

@@ -0,0 +1,97 @@
+package com.baeldung.hamcrest;
+
+import org.junit.Test;
+
+import static org.hamcrest.core.StringContains.containsString;
+import static org.hamcrest.core.StringContains.containsStringIgnoringCase;
+import static org.hamcrest.core.StringEndsWith.endsWith;
+import static org.hamcrest.core.StringEndsWith.endsWithIgnoringCase;
+import static org.hamcrest.core.StringStartsWith.startsWith;
+import static org.hamcrest.core.StringStartsWith.startsWithIgnoringCase;
+import static org.hamcrest.text.IsBlankString.blankOrNullString;
+import static org.hamcrest.text.IsBlankString.blankString;
+import static org.hamcrest.text.IsEmptyString.emptyOrNullString;
+import static org.hamcrest.text.IsEmptyString.emptyString;
+import static org.hamcrest.text.IsEqualIgnoringCase.equalToIgnoringCase;
+import static org.hamcrest.text.IsEqualIgnoringWhiteSpace.equalToIgnoringWhiteSpace;
+import static org.hamcrest.text.MatchesPattern.matchesPattern;
+import static org.hamcrest.text.StringContainsInOrder.stringContainsInOrder;
+import static org.junit.Assert.assertThat;
+
+public class HamcrestTextUnitTest {
+    
+    @Test
+    public final void whenTwoStringsAreEqual_thenCorrect() {
+        String first = "hello";
+        String second = "Hello";
+        
+        assertThat(first, equalToIgnoringCase(second));
+    }
+
+    @Test
+    public final void whenTwoStringsAreEqualWithWhiteSpace_thenCorrect() {
+        String first = "hello";
+        String second = "   Hello   ";
+        
+        assertThat(first, equalToIgnoringWhiteSpace(second));
+    }
+
+    @Test
+    public final void whenStringIsBlank_thenCorrect() {
+        String first = "  ";
+        String second = null;
+
+        assertThat(first, blankString());
+        assertThat(first, blankOrNullString());
+        assertThat(second, blankOrNullString());
+    }
+
+    @Test
+    public final void whenStringIsEmpty_thenCorrect() {
+        String first = "";
+        String second = null;
+
+        assertThat(first, emptyString());
+        assertThat(first, emptyOrNullString());
+        assertThat(second, emptyOrNullString());
+    }
+
+    @Test
+    public final void whenStringMatchPattern_thenCorrect() {
+        String first = "hello";
+
+        assertThat(first, matchesPattern("[a-z]+"));
+    }
+
+    @Test
+    public final void whenVerifyStringContains_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, containsString("lo"));
+        assertThat(first, containsStringIgnoringCase("EL"));
+    }
+    
+    @Test
+    public final void whenVerifyStringContainsInOrder_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, stringContainsInOrder("e","l","o"));
+    }
+    
+    @Test
+    public final void whenVerifyStringStartsWith_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, startsWith("he"));
+        assertThat(first, startsWithIgnoringCase("HEL"));
+    }
+    
+    @Test
+    public final void whenVerifyStringEndsWith_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, endsWith("lo"));
+        assertThat(first, endsWithIgnoringCase("LO"));
+    }
+    
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/custommatchers/HamcrestCustomUnitTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.hamcrest.custommatchers;
+
+import org.junit.Test;
+
+import static com.baeldung.hamcrest.custommatchers.IsDivisibleBy.divisibleBy;
+import static com.baeldung.hamcrest.custommatchers.IsOnlyDigits.onlyDigits;
+import static com.baeldung.hamcrest.custommatchers.IsUppercase.uppercase;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.not;
+
+public class HamcrestCustomUnitTest {
+
+    @Test
+    public final void givenAString_whenIsOnlyDigits_thenCorrect() {
+        String digits = "123";
+
+        assertThat(digits, is(onlyDigits()));
+    }
+
+    @Test
+    public final void givenAString_whenIsNotOnlyDigits_thenCorrect() {
+        String aphanumeric = "123ABC";
+
+        assertThat(aphanumeric, is(not(onlyDigits())));
+    }
+
+    @Test
+    public final void givenAString_whenIsUppercase_thenCorrect() {
+        String uppercaseWord = "HELLO";
+
+        assertThat(uppercaseWord, is(uppercase()));
+    }
+
+    @Test
+    public final void givenAnEvenInteger_whenDivisibleByTwo_thenCorrect() {
+        Integer ten = 10;
+        Integer two = 2;
+
+        assertThat(ten, is(divisibleBy(two)));
+    }
+
+    @Test
+    public final void givenAnOddInteger_whenNotDivisibleByTwo_thenCorrect() {
+        Integer eleven = 11;
+        Integer two = 2;
+
+        assertThat(eleven, is(not(divisibleBy(two))));
+    }
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/custommatchers/IsDivisibleBy.java

@@ -0,0 +1,29 @@
+package com.baeldung.hamcrest.custommatchers;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+
+public class IsDivisibleBy extends TypeSafeMatcher<Integer> {
+
+    private Integer divider;
+
+    private IsDivisibleBy(Integer divider) {
+        this.divider = divider;
+    }
+
+    @Override
+    protected boolean matchesSafely(Integer dividend) {
+        if (divider == 0) return false;
+        return ((dividend % divider) == 0);
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText("divisible by " + divider);
+    }
+
+    public static Matcher<Integer> divisibleBy(Integer divider) {
+        return new IsDivisibleBy(divider);
+    }
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/custommatchers/IsOnlyDigits.java

@@ -0,0 +1,27 @@
+package com.baeldung.hamcrest.custommatchers;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+
+public class IsOnlyDigits extends TypeSafeMatcher<String> {
+
+    @Override
+    protected boolean matchesSafely(String s) {
+        try {
+            Integer.parseInt(s);
+            return true;
+        } catch (NumberFormatException nfe) {
+            return false;
+        }
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText("only digits");
+    }
+
+    public static Matcher<String> onlyDigits() {
+        return new IsOnlyDigits();
+    }
+}

testing-modules/hamcrest/src/test/java/com/baeldung/hamcrest/custommatchers/IsUppercase.java

@@ -0,0 +1,22 @@
+package com.baeldung.hamcrest.custommatchers;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+
+public class IsUppercase extends TypeSafeMatcher<String> {
+
+    @Override
+    protected boolean matchesSafely(String s) {
+        return s.equals(s.toUpperCase());
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText("all uppercase");
+    }
+
+    public static Matcher<String> uppercase() {
+        return new IsUppercase();
+    }
+}

testing-modules/hamcrest/src/test/resources/test1.in

@@ -0,0 +1 @@
+Hello world

testing-modules/junit-4/README.md

@@ -0,0 +1,6 @@
+### Relevant Articles
+
+- [Guide to JUnit 4 Rules](https://www.baeldung.com/junit-4-rules)
+- [Custom JUnit 4 Test Runners](http://www.baeldung.com/junit-4-custom-runners)
+- [Introduction to JUnitParams](http://www.baeldung.com/junit-params)
+- [Running JUnit Tests Programmatically, from a Java Application](https://www.baeldung.com/junit-tests-run-programmatically-from-java)

testing-modules/junit-4/pom.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>junit-4</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>junit-4</name>
+    <description>JUnit 4 Topics</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>pl.pragmatists</groupId>
+            <artifactId>JUnitParams</artifactId>
+            <version>${jUnitParams.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <jUnitParams.version>1.1.0</jUnitParams.version>
+    </properties>
+
+</project>

testing-modules/junit-4/src/main/java/com/baeldung/junit/Calculator.java

@@ -0,0 +1,11 @@
+package com.baeldung.junit;
+
+public class Calculator {
+    public int add(int a, int b) {
+        return a + b;
+    }
+
+    public int sub(int a, int b) {
+        return a - b;
+    }
+}

testing-modules/junit-4/src/main/java/com/baeldung/junitparams/SafeAdditionUtil.java

@@ -0,0 +1,15 @@
+package com.baeldung.junitparams;
+
+public class SafeAdditionUtil {
+
+    public int safeAdd(int a, int b) {
+        long result = ((long) a) + b;
+        if (result > Integer.MAX_VALUE) {
+            return Integer.MAX_VALUE;
+        } else if (result < Integer.MIN_VALUE) {
+            return Integer.MIN_VALUE;
+        }
+        return (int) result;
+    }
+
+}

testing-modules/junit-4/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

testing-modules/junit-4/src/test/java/com/baeldung/junit/AdditionUnitTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.junit;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class AdditionUnitTest {
+    Calculator calculator = new Calculator();
+
+    @Test
+    public void testAddition() {
+        assertEquals("addition", 8, calculator.add(5, 3));
+    }
+}