Update README.md

libraries-data-2/src/test/java/com/baeldung/crdt/CRDTUnitTest.java

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+package com.baeldung.crdt;
+
+import com.netopyr.wurmloch.crdt.GCounter;
+import com.netopyr.wurmloch.crdt.GSet;
+import com.netopyr.wurmloch.crdt.LWWRegister;
+import com.netopyr.wurmloch.crdt.PNCounter;
+import com.netopyr.wurmloch.store.LocalCrdtStore;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CRDTUnitTest {
+
+    @Test
+    public void givenGrowOnlySet_whenTwoReplicasDiverge_thenShouldMergeItWithoutAConflict() {
+        // given
+        final LocalCrdtStore crdtStore1 = new LocalCrdtStore();
+        final LocalCrdtStore crdtStore2 = new LocalCrdtStore();
+        crdtStore1.connect(crdtStore2);
+
+        final GSet<String> replica1 = crdtStore1.createGSet("ID_1");
+        final GSet<String> replica2 = crdtStore2.<String> findGSet("ID_1").get();
+
+        // when
+        replica1.add("apple");
+        replica2.add("banana");
+
+        // then
+        assertThat(replica1).contains("apple", "banana");
+        assertThat(replica2).contains("apple", "banana");
+
+        // when
+        crdtStore1.disconnect(crdtStore2);
+
+        replica1.add("strawberry");
+        replica2.add("pear");
+
+        assertThat(replica1).contains("apple", "banana", "strawberry");
+        assertThat(replica2).contains("apple", "banana", "pear");
+
+        crdtStore1.connect(crdtStore2);
+
+        // then
+        assertThat(replica1).contains("apple", "banana", "strawberry", "pear");
+        assertThat(replica2).contains("apple", "banana", "strawberry", "pear");
+    }
+
+    @Test
+    public void givenIncrementOnlyCounter_whenTwoReplicasDiverge_thenShouldMergeIt() {
+        // given
+        final LocalCrdtStore crdtStore1 = new LocalCrdtStore();
+        final LocalCrdtStore crdtStore2 = new LocalCrdtStore();
+        crdtStore1.connect(crdtStore2);
+
+        final GCounter replica1 = crdtStore1.createGCounter("ID_1");
+        final GCounter replica2 = crdtStore2.findGCounter("ID_1").get();
+
+        // when
+        replica1.increment();
+        replica2.increment(2L);
+
+        // then
+        assertThat(replica1.get()).isEqualTo(3L);
+        assertThat(replica2.get()).isEqualTo(3L);
+
+        // when
+        crdtStore1.disconnect(crdtStore2);
+
+        replica1.increment(3L);
+        replica2.increment(5L);
+
+        assertThat(replica1.get()).isEqualTo(6L);
+        assertThat(replica2.get()).isEqualTo(8L);
+
+        crdtStore1.connect(crdtStore2);
+
+        // then
+        assertThat(replica1.get()).isEqualTo(11L);
+        assertThat(replica2.get()).isEqualTo(11L);
+    }
+
+    @Test
+    public void givenPNCounter_whenReplicasDiverge_thenShouldMergeWithoutAConflict() {
+        // given
+        final LocalCrdtStore crdtStore1 = new LocalCrdtStore();
+        final LocalCrdtStore crdtStore2 = new LocalCrdtStore();
+        crdtStore1.connect(crdtStore2);
+
+        final PNCounter replica1 = crdtStore1.createPNCounter("ID_1");
+        final PNCounter replica2 = crdtStore2.findPNCounter("ID_1").get();
+
+        // when
+        replica1.increment();
+        replica2.decrement(2L);
+
+        // then
+        assertThat(replica1.get()).isEqualTo(-1L);
+        assertThat(replica2.get()).isEqualTo(-1L);
+
+        // when
+        crdtStore1.disconnect(crdtStore2);
+
+        replica1.decrement(3L);
+        replica2.increment(5L);
+
+        assertThat(replica1.get()).isEqualTo(-4L);
+        assertThat(replica2.get()).isEqualTo(4L);
+
+        crdtStore1.connect(crdtStore2);
+
+        // then
+        assertThat(replica1.get()).isEqualTo(1L);
+        assertThat(replica2.get()).isEqualTo(1L);
+    }
+
+    @Test
+    public void givenLastWriteWinsStrategy_whenReplicasDiverge_thenAfterMergeShouldKeepOnlyLastValue() {
+        // given
+        final LocalCrdtStore crdtStore1 = new LocalCrdtStore("N_1");
+        final LocalCrdtStore crdtStore2 = new LocalCrdtStore("N_2");
+        crdtStore1.connect(crdtStore2);
+
+        final LWWRegister<String> replica1 = crdtStore1.createLWWRegister("ID_1");
+        final LWWRegister<String> replica2 = crdtStore2.<String> findLWWRegister("ID_1").get();
+
+        // when
+        replica1.set("apple");
+        replica2.set("banana");
+
+        // then
+        assertThat(replica1.get()).isEqualTo("banana");
+        assertThat(replica2.get()).isEqualTo("banana");
+
+        // when
+        crdtStore1.disconnect(crdtStore2);
+
+        replica1.set("strawberry");
+        replica2.set("pear");
+
+        assertThat(replica1.get()).isEqualTo("strawberry");
+        assertThat(replica2.get()).isEqualTo("pear");
+
+        crdtStore1.connect(crdtStore2);
+
+        // then
+        assertThat(replica1.get()).isEqualTo("pear");
+        assertThat(replica2.get()).isEqualTo("pear");
+    }
+}

libraries-data-2/src/test/java/com/baeldung/derive4j/adt/EitherUnitTest.java

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+package com.baeldung.derive4j.adt;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.util.Optional;
+import java.util.function.Function;
+
+@RunWith(MockitoJUnitRunner.class)
+public class EitherUnitTest {
+    @Test
+    public void testEitherIsCreatedFromRight() {
+       Either<Exception, String> either = Eithers.right("Okay");
+       Optional<Exception> leftOptional = Eithers.getLeft(either);
+       Optional<String> rightOptional = Eithers.getRight(either);
+       Assertions.assertThat(leftOptional).isEmpty();
+       Assertions.assertThat(rightOptional).hasValue("Okay");
+
+    }
+
+    @Test
+    public void testEitherIsMatchedWithRight() {
+        Either<Exception, String> either = Eithers.right("Okay");
+        Function<Exception, String> leftFunction = Mockito.mock(Function.class);
+        Function<String, String> rightFunction = Mockito.mock(Function.class);
+        either.match(leftFunction, rightFunction);
+        Mockito.verify(rightFunction, Mockito.times(1)).apply("Okay");
+        Mockito.verify(leftFunction, Mockito.times(0)).apply(Mockito.any(Exception.class));
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/derive4j/lazy/LazyRequestUnitTest.java

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+package com.baeldung.derive4j.lazy;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.util.function.Supplier;
+
+public class LazyRequestUnitTest {
+
+    @Test
+    public void givenLazyContstructedRequest_whenRequestIsReferenced_thenRequestIsLazilyContructed() {
+        LazyRequestSupplier mockSupplier = Mockito.spy(new LazyRequestSupplier());
+
+        LazyRequest request = LazyRequestImpl.lazy(() -> mockSupplier.get());
+        Mockito.verify(mockSupplier, Mockito.times(0)).get();
+        Assert.assertEquals(LazyRequestImpl.getPath(request), "http://test.com/get");
+        Mockito.verify(mockSupplier, Mockito.times(1)).get();
+
+    }
+
+    class LazyRequestSupplier implements Supplier<LazyRequest> {
+        @Override
+        public LazyRequest get() {
+            return LazyRequestImpl.GET("http://test.com/get");
+        }
+    }
+}

libraries-data-2/src/test/java/com/baeldung/derive4j/pattern/HTTPRequestUnitTest.java

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+package com.baeldung.derive4j.pattern;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class HTTPRequestUnitTest {
+    public static HTTPServer server;
+
+    @BeforeClass
+    public static void setUp() {
+        server = new HTTPServer();
+    }
+
+    @Test
+    public void givenHttpGETRequest_whenRequestReachesServer_thenProperResponseIsReturned() {
+        HTTPRequest postRequest = HTTPRequests.POST("http://test.com/post", "Resource");
+        HTTPResponse response = server.acceptRequest(postRequest);
+        Assert.assertEquals(201, response.getStatusCode());
+        Assert.assertEquals(HTTPServer.POST_RESPONSE_BODY, response.getResponseBody());
+    }
+}

libraries-data-2/src/test/java/com/baeldung/flink/BackupCreatorIntegrationTest.java

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+package com.baeldung.flink;
+
+import com.baeldung.flink.model.Backup;
+import com.baeldung.flink.model.InputMessage;
+import com.baeldung.flink.operator.BackupAggregator;
+import com.baeldung.flink.operator.InputMessageTimestampAssigner;
+import com.baeldung.flink.schema.BackupSerializationSchema;
+import com.baeldung.flink.schema.InputMessageDeserializationSchema;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.apache.commons.collections.ListUtils;
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.serialization.SerializationSchema;
+import org.apache.flink.streaming.api.TimeCharacteristic;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.SinkFunction;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.awaitility.Awaitility;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+public class BackupCreatorIntegrationTest {
+    public static ObjectMapper mapper;
+
+    @Before
+    public void setup() {
+        mapper = new ObjectMapper().registerModule(new JavaTimeModule());
+    }
+
+    @Test
+    public void givenProperJson_whenDeserializeIsInvoked_thenProperObjectIsReturned() throws IOException {
+        InputMessage message = new InputMessage("Me", "User", LocalDateTime.now(), "Test Message");
+        byte[] messageSerialized = mapper.writeValueAsBytes(message);
+        DeserializationSchema<InputMessage> deserializationSchema = new InputMessageDeserializationSchema();
+        InputMessage messageDeserialized = deserializationSchema.deserialize(messageSerialized);
+
+        assertEquals(message, messageDeserialized);
+    }
+
+    @Test
+    public void givenMultipleInputMessagesFromDifferentDays_whenBackupCreatorIsUser_thenMessagesAreGroupedProperly() throws Exception {
+        LocalDateTime currentTime = LocalDateTime.now();
+        InputMessage message = new InputMessage("Me", "User", currentTime, "First TestMessage");
+        InputMessage secondMessage = new InputMessage("Me", "User", currentTime.plusHours(1), "First TestMessage");
+        InputMessage thirdMessage = new InputMessage("Me", "User", currentTime.plusHours(2), "First TestMessage");
+        InputMessage fourthMessage = new InputMessage("Me", "User", currentTime.plusHours(3), "First TestMessage");
+        InputMessage fifthMessage = new InputMessage("Me", "User", currentTime.plusHours(25), "First TestMessage");
+        InputMessage sixthMessage = new InputMessage("Me", "User", currentTime.plusHours(26), "First TestMessage");
+
+        List<InputMessage> firstBackupMessages = Arrays.asList(message, secondMessage, thirdMessage, fourthMessage);
+        List<InputMessage> secondBackupMessages = Arrays.asList(fifthMessage, sixthMessage);
+        List<InputMessage> inputMessages = ListUtils.union(firstBackupMessages, secondBackupMessages);
+
+        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+        env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
+        env.setParallelism(1);
+        DataStreamSource<InputMessage> testDataSet = env.fromCollection(inputMessages);
+        CollectingSink sink = new CollectingSink();
+        testDataSet.assignTimestampsAndWatermarks(new InputMessageTimestampAssigner())
+          .timeWindowAll(Time.hours(24))
+          .aggregate(new BackupAggregator())
+          .addSink(sink);
+
+        env.execute();
+
+        Awaitility.await().until(() ->  sink.backups.size() == 2);
+        assertEquals(2, sink.backups.size());
+        assertEquals(firstBackupMessages, sink.backups.get(0).getInputMessages());
+        assertEquals(secondBackupMessages, sink.backups.get(1).getInputMessages());
+
+    }
+
+    @Test
+    public void givenProperBackupObject_whenSerializeIsInvoked_thenObjectIsProperlySerialized() throws IOException {
+        InputMessage message = new InputMessage("Me", "User", LocalDateTime.now(), "Test Message");
+        List<InputMessage> messages = Arrays.asList(message);
+        Backup backup = new Backup(messages, LocalDateTime.now());
+        byte[] backupSerialized = mapper.writeValueAsBytes(backup);
+        SerializationSchema<Backup> serializationSchema = new BackupSerializationSchema();
+        byte[] backupProcessed = serializationSchema.serialize(backup);
+        
+        assertArrayEquals(backupSerialized, backupProcessed);
+    }
+
+    private static class CollectingSink implements SinkFunction<Backup> {
+        
+        public static List<Backup> backups = new ArrayList<>();
+
+        @Override
+        public synchronized void invoke(Backup value, Context context) throws Exception {
+            backups.add(value);
+        }
+    }
+}

libraries-data-2/src/test/java/com/baeldung/flink/WordCapitalizerIntegrationTest.java

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+package com.baeldung.flink;
+
+import com.baeldung.flink.operator.WordsCapitalizer;
+import org.apache.flink.api.java.DataSet;
+import org.apache.flink.api.java.ExecutionEnvironment;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class WordCapitalizerIntegrationTest {
+
+    @Test
+    public void givenDataSet_whenExecuteWordCapitalizer_thenReturnCapitalizedWords() throws Exception {
+        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
+        List<String> data = Arrays.asList("dog", "cat", "wolf", "pig");
+
+         DataSet<String> testDataSet = env.fromCollection(data);
+
+
+        List<String> dataProcessed = testDataSet
+          .map(new WordsCapitalizer())
+          .collect();
+
+        List<String> testDataCapitalized = data.stream()
+          .map(String::toUpperCase)
+          .collect(Collectors.toList());
+
+        Assert.assertEquals(testDataCapitalized, dataProcessed);
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/flink/WordCountIntegrationTest.java

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+package com.baeldung.flink;
+
+import org.apache.flink.api.common.operators.Order;
+import org.apache.flink.api.java.DataSet;
+import org.apache.flink.api.java.ExecutionEnvironment;
+import org.apache.flink.api.java.functions.KeySelector;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.tuple.Tuple3;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.timestamps.BoundedOutOfOrdernessTimestampExtractor;
+import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.junit.Test;
+
+import java.time.ZonedDateTime;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class WordCountIntegrationTest {
+    private final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
+
+    @Test
+    public void givenDataSet_whenExecuteWordCount_thenReturnWordCount() throws Exception {
+        // given
+        List<String> lines = Arrays.asList("This is a first sentence", "This is a second sentence with a one word");
+
+        // when
+        DataSet<Tuple2<String, Integer>> result = WordCount.startWordCount(env, lines);
+
+        // then
+        List<Tuple2<String, Integer>> collect = result.collect();
+        assertThat(collect).containsExactlyInAnyOrder(new Tuple2<>("a", 3), new Tuple2<>("sentence", 2), new Tuple2<>("word", 1), new Tuple2<>("is", 2), new Tuple2<>("this", 2), new Tuple2<>("second", 1), new Tuple2<>("first", 1), new Tuple2<>("with", 1),
+                new Tuple2<>("one", 1));
+    }
+
+    @Test
+    public void givenListOfAmounts_whenUseMapReduce_thenSumAmountsThatAreOnlyAboveThreshold() throws Exception {
+        // given
+        DataSet<Integer> amounts = env.fromElements(1, 29, 40, 50);
+        int threshold = 30;
+
+        // when
+        List<Integer> collect = amounts.filter(a -> a > threshold).reduce((integer, t1) -> integer + t1).collect();
+
+        // then
+        assertThat(collect.get(0)).isEqualTo(90);
+    }
+
+    @Test
+    public void givenDataSetOfComplexObjects_whenMapToGetOneField_thenReturnedListHaveProperElements() throws Exception {
+        // given
+        DataSet<Person> personDataSource = env.fromCollection(Arrays.asList(new Person(23, "Tom"), new Person(75, "Michael")));
+
+        // when
+        List<Integer> ages = personDataSource.map(p -> p.age).collect();
+
+        // then
+        assertThat(ages).hasSize(2);
+        assertThat(ages).contains(23, 75);
+
+    }
+
+    @Test
+    public void givenDataSet_whenSortItByOneField_thenShouldReturnSortedDataSet() throws Exception {
+        // given
+        Tuple2<Integer, String> secondPerson = new Tuple2<>(4, "Tom");
+        Tuple2<Integer, String> thirdPerson = new Tuple2<>(5, "Scott");
+        Tuple2<Integer, String> fourthPerson = new Tuple2<>(200, "Michael");
+        Tuple2<Integer, String> firstPerson = new Tuple2<>(1, "Jack");
+        DataSet<Tuple2<Integer, String>> transactions = env.fromElements(fourthPerson, secondPerson, thirdPerson, firstPerson);
+
+        // when
+        List<Tuple2<Integer, String>> sorted = transactions.sortPartition(new IdKeySelectorTransaction(), Order.ASCENDING).collect();
+
+        // then
+        assertThat(sorted).containsExactly(firstPerson, secondPerson, thirdPerson, fourthPerson);
+    }
+
+    @Test
+    public void giveTwoDataSets_whenJoinUsingId_thenProduceJoinedData() throws Exception {
+        // given
+        Tuple3<Integer, String, String> address = new Tuple3<>(1, "5th Avenue", "London");
+        DataSet<Tuple3<Integer, String, String>> addresses = env.fromElements(address);
+
+        Tuple2<Integer, String> firstTransaction = new Tuple2<>(1, "Transaction_1");
+        DataSet<Tuple2<Integer, String>> transactions = env.fromElements(firstTransaction, new Tuple2<>(12, "Transaction_2"));
+
+        // when
+        List<Tuple2<Tuple2<Integer, String>, Tuple3<Integer, String, String>>> joined = transactions.join(addresses).where(new IdKeySelectorTransaction()).equalTo(new IdKeySelectorAddress()).collect();
+
+        // then
+        assertThat(joined).hasSize(1);
+        assertThat(joined).contains(new Tuple2<>(firstTransaction, address));
+
+    }
+
+    @Test
+    public void givenStreamOfEvents_whenProcessEvents_thenShouldPrintResultsOnSinkOperation() throws Exception {
+        // given
+        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+        DataStream<String> text = env.fromElements("This is a first sentence", "This is a second sentence with a one word");
+
+        SingleOutputStreamOperator<String> upperCase = text.map(String::toUpperCase);
+
+        upperCase.print();
+
+        // when
+        env.execute();
+    }
+
+    @Test
+    public void givenStreamOfEvents_whenProcessEvents_thenShouldApplyWindowingOnTransformation() throws Exception {
+        // given
+        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+
+        SingleOutputStreamOperator<Tuple2<Integer, Long>> windowed = env.fromElements(new Tuple2<>(16, ZonedDateTime.now().plusMinutes(25).toInstant().getEpochSecond()), new Tuple2<>(15, ZonedDateTime.now().plusMinutes(2).toInstant().getEpochSecond()))
+                .assignTimestampsAndWatermarks(new BoundedOutOfOrdernessTimestampExtractor<Tuple2<Integer, Long>>(Time.seconds(20)) {
+                    @Override
+                    public long extractTimestamp(Tuple2<Integer, Long> element) {
+                        return element.f1 * 1000;
+                    }
+                });
+
+        SingleOutputStreamOperator<Tuple2<Integer, Long>> reduced = windowed.windowAll(TumblingEventTimeWindows.of(Time.seconds(5))).maxBy(0, true);
+
+        reduced.print();
+
+        // when
+        env.execute();
+    }
+
+    private static class IdKeySelectorTransaction implements KeySelector<Tuple2<Integer, String>, Integer> {
+        @Override
+        public Integer getKey(Tuple2<Integer, String> value) {
+            return value.f0;
+        }
+    }
+
+    private static class IdKeySelectorAddress implements KeySelector<Tuple3<Integer, String, String>, Integer> {
+        @Override
+        public Integer getKey(Tuple3<Integer, String, String> value) {
+            return value.f0;
+        }
+    }
+
+    private static class Person {
+        private final int age;
+        private final String name;
+
+        private Person(int age, String name) {
+            this.age = age;
+            this.name = name;
+        }
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/hll/HLLLongRunningManualTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.hll;
+
+import com.google.common.hash.HashFunction;
+import com.google.common.hash.Hashing;
+import net.agkn.hll.HLL;
+import org.assertj.core.data.Offset;
+import org.junit.Test;
+
+import java.util.stream.LongStream;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+public class HLLLongRunningManualTest {
+
+    @Test
+    public void givenHLL_whenAddHugeAmountOfNumbers_thenShouldReturnEstimatedCardinality() {
+        // given
+        long numberOfElements = 100_000_000;
+        long toleratedDifference = 1_000_000;
+        HashFunction hashFunction = Hashing.murmur3_128();
+        HLL hll = new HLL(14, 5);
+
+        // when
+        LongStream.range(0, numberOfElements).forEach(element -> {
+            long hashedValue = hashFunction.newHasher().putLong(element).hash().asLong();
+            hll.addRaw(hashedValue);
+        });
+
+        // then
+        long cardinality = hll.cardinality();
+        assertThat(cardinality).isCloseTo(numberOfElements, Offset.offset(toleratedDifference));
+    }
+
+    @Test
+    public void givenTwoHLLs_whenAddHugeAmountOfNumbers_thenShouldReturnEstimatedCardinalityForUnionOfHLLs() {
+        // given
+        long numberOfElements = 100_000_000;
+        long toleratedDifference = 1_000_000;
+        HashFunction hashFunction = Hashing.murmur3_128();
+        HLL firstHll = new HLL(15, 5);
+        HLL secondHLL = new HLL(15, 5);
+
+        // when
+        LongStream.range(0, numberOfElements).forEach(element -> {
+            long hashedValue = hashFunction.newHasher().putLong(element).hash().asLong();
+            firstHll.addRaw(hashedValue);
+        });
+
+        LongStream.range(numberOfElements, numberOfElements * 2).forEach(element -> {
+            long hashedValue = hashFunction.newHasher().putLong(element).hash().asLong();
+            secondHLL.addRaw(hashedValue);
+        });
+
+        // then
+        firstHll.union(secondHLL);
+        long cardinality = firstHll.cardinality();
+        assertThat(cardinality).isCloseTo(numberOfElements * 2, Offset.offset(toleratedDifference * 2));
+    }
+}

libraries-data-2/src/test/java/com/baeldung/infinispan/AbstractIntegrationTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.infinispan;
+
+import com.baeldung.infinispan.listener.CacheListener;
+import com.baeldung.infinispan.repository.HelloWorldRepository;
+import com.baeldung.infinispan.service.HelloWorldService;
+import com.baeldung.infinispan.service.TransactionalService;
+import org.infinispan.Cache;
+import org.infinispan.manager.DefaultCacheManager;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Ignore;
+
+import java.util.function.Supplier;
+
+@Ignore
+public abstract class AbstractIntegrationTest {
+
+    private DefaultCacheManager cacheManager;
+
+    private HelloWorldRepository repository = new HelloWorldRepository();
+
+    protected HelloWorldService helloWorldService;
+    protected TransactionalService transactionalService;
+
+    @Before
+    public void setup() {
+        CacheConfiguration configuration = new CacheConfiguration();
+        CacheListener listener = new CacheListener();
+
+        cacheManager = configuration.cacheManager();
+
+        Cache<String, Integer> transactionalCache = configuration.transactionalCache(cacheManager, listener);
+
+        Cache<String, String> simpleHelloWorldCache = configuration.simpleHelloWorldCache(cacheManager, listener);
+
+        Cache<String, String> expiringHelloWorldCache = configuration.expiringHelloWorldCache(cacheManager, listener);
+
+        Cache<String, String> evictingHelloWorldCache = configuration.evictingHelloWorldCache(cacheManager, listener);
+
+        Cache<String, String> passivatingHelloWorldCache = configuration.passivatingHelloWorldCache(cacheManager, listener);
+
+        this.helloWorldService = new HelloWorldService(repository, listener, simpleHelloWorldCache, expiringHelloWorldCache, evictingHelloWorldCache, passivatingHelloWorldCache);
+
+        this.transactionalService = new TransactionalService(transactionalCache);
+    }
+
+    @After
+    public void tearDown() {
+        cacheManager.stop();
+    }
+
+    protected <T> long timeThis(Supplier<T> supplier) {
+        long millis = System.currentTimeMillis();
+        supplier.get();
+        return System.currentTimeMillis() - millis;
+    }
+}

libraries-data-2/src/test/java/com/baeldung/infinispan/service/HelloWorldServiceTemporaryLiveTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.infinispan.service;
+
+import com.baeldung.infinispan.AbstractIntegrationTest;
+import org.junit.Test;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+
+public class HelloWorldServiceTemporaryLiveTest extends AbstractIntegrationTest {
+
+    @Test
+    public void whenGetIsCalledTwoTimes_thenTheSecondShouldHitTheCache() {
+        assertThat(timeThis(() -> helloWorldService.findSimpleHelloWorld())).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findSimpleHelloWorld())).isLessThan(100);
+    }
+
+    @Test
+    public void whenGetIsCalledTwoTimesQuickly_thenTheSecondShouldHitTheCache() {
+        assertThat(timeThis(() -> helloWorldService.findExpiringHelloWorld())).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findExpiringHelloWorld())).isLessThan(100);
+    }
+
+    @Test
+    public void whenGetIsCalledTwoTimesSparsely_thenNeitherShouldHitTheCache() throws InterruptedException {
+        assertThat(timeThis(() -> helloWorldService.findExpiringHelloWorld())).isGreaterThanOrEqualTo(1000);
+
+        Thread.sleep(1100);
+
+        assertThat(timeThis(() -> helloWorldService.findExpiringHelloWorld())).isGreaterThanOrEqualTo(1000);
+    }
+
+    @Test
+    public void givenOneEntryIsConfigured_whenTwoAreAdded_thenFirstShouldntBeAvailable() {
+        assertThat(timeThis(() -> helloWorldService.findEvictingHelloWorld("key 1"))).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findEvictingHelloWorld("key 2"))).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findEvictingHelloWorld("key 1"))).isGreaterThanOrEqualTo(1000);
+    }
+
+    @Test
+    public void givenOneEntryIsConfigured_whenTwoAreAdded_thenTheFirstShouldBeAvailable() {
+        assertThat(timeThis(() -> helloWorldService.findPassivatingHelloWorld("key 1"))).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findPassivatingHelloWorld("key 2"))).isGreaterThanOrEqualTo(1000);
+
+        assertThat(timeThis(() -> helloWorldService.findPassivatingHelloWorld("key 1"))).isLessThan(100);
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/infinispan/service/TransactionalServiceIntegrationTest.java

@@ -0,0 +1,21 @@
+package com.baeldung.infinispan.service;
+
+import com.baeldung.infinispan.AbstractIntegrationTest;
+import org.junit.Test;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+
+public class TransactionalServiceIntegrationTest extends AbstractIntegrationTest {
+
+    @Test
+    public void whenLockingAnEntry_thenItShouldBeInaccessible() throws InterruptedException {
+        Runnable backGroundJob = () -> transactionalService.startBackgroundBatch();
+        Thread backgroundThread = new Thread(backGroundJob);
+        transactionalService.getQuickHowManyVisits();
+        backgroundThread.start();
+        Thread.sleep(100); // lets wait our thread warm up
+
+        assertThat(timeThis(() -> transactionalService.getQuickHowManyVisits())).isGreaterThan(500).isLessThan(1000);
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/jmapper/JMapperIntegrationTest.java

@@ -0,0 +1,99 @@
+package com.baeldung.jmapper;
+
+import com.googlecode.jmapper.JMapper;
+import com.googlecode.jmapper.api.JMapperAPI;
+import org.junit.Test;
+
+import java.time.LocalDate;
+
+import static com.googlecode.jmapper.api.JMapperAPI.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class JMapperIntegrationTest {
+
+    @Test
+    public void givenUser_whenUseAnnotation_thenConverted() {
+        JMapper<UserDto, User> userMapper = new JMapper<>(UserDto.class, User.class);
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getUsername());
+    }
+
+    @Test
+    public void givenUser_whenUseGlobalMapAnnotation_thenConverted() {
+        JMapper<UserDto1, User> userMapper = new JMapper<>(UserDto1.class, User.class);
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto1 result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getEmail());
+    }
+
+    @Test
+    public void givenUser_whenUseAnnotationExplicitConversion_thenConverted() {
+        JMapper<UserDto, User> userMapper = new JMapper<>(UserDto.class, User.class);
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getUsername());
+        assertTrue(result.getAge() > 0);
+    }
+
+    // ======================= XML
+
+    @Test
+    public void givenUser_whenUseXml_thenConverted() {
+        JMapper<UserDto, User> userMapper = new JMapper<>(UserDto.class, User.class, "user_jmapper.xml");
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getUsername());
+    }
+
+    @Test
+    public void givenUser_whenUseXmlGlobal_thenConverted() {
+        JMapper<UserDto1, User> userMapper = new JMapper<>(UserDto1.class, User.class, "user_jmapper1.xml");
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto1 result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getEmail());
+    }
+
+    // ===== API
+
+    @Test
+    public void givenUser_whenUseApi_thenConverted() {
+        JMapperAPI jmapperApi = new JMapperAPI().add(mappedClass(UserDto.class).add(attribute("id").value("id")).add(attribute("username").value("email")));
+        JMapper<UserDto, User> userMapper = new JMapper<>(UserDto.class, User.class, jmapperApi);
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto result = userMapper.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getUsername());
+    }
+
+    @Test
+    public void givenUser_whenUseApiGlobal_thenConverted() {
+        JMapperAPI jmapperApi = new JMapperAPI().add(mappedClass(UserDto.class).add(global()));
+        JMapper<UserDto1, User> userMapper1 = new JMapper<>(UserDto1.class, User.class, jmapperApi);
+
+        User user = new User(1L, "john@test.com", LocalDate.of(1980, 8, 20));
+        UserDto1 result = userMapper1.getDestination(user);
+
+        assertEquals(user.getId(), result.getId());
+        assertEquals(user.getEmail(), result.getEmail());
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/jmapper/JMapperRelationalIntegrationTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.jmapper;
+
+import com.baeldung.jmapper.relational.User;
+import com.baeldung.jmapper.relational.UserDto1;
+import com.baeldung.jmapper.relational.UserDto2;
+import com.googlecode.jmapper.RelationalJMapper;
+import com.googlecode.jmapper.api.JMapperAPI;
+import org.junit.Test;
+
+import static com.googlecode.jmapper.api.JMapperAPI.attribute;
+import static com.googlecode.jmapper.api.JMapperAPI.mappedClass;
+import static org.junit.Assert.assertEquals;
+
+public class JMapperRelationalIntegrationTest {
+
+    
+    @Test
+    public void givenUser_whenUseAnnotation_thenConverted(){
+        RelationalJMapper<User> relationalMapper = new RelationalJMapper<>(User.class);
+        
+        User user = new User(1L,"john@test.com");
+        UserDto1 result1 = relationalMapper.oneToMany(UserDto1.class, user);
+        UserDto2 result2= relationalMapper.oneToMany(UserDto2.class, user);
+
+        System.out.println(result1);
+        System.out.println(result2);
+        assertEquals(user.getId(), result1.getId());
+        assertEquals(user.getEmail(), result1.getUsername());  
+        assertEquals(user.getId(), result2.getId());
+        assertEquals(user.getEmail(), result2.getEmail());          
+    }     
+
+    //======================= XML
+    
+    @Test
+    public void givenUser_whenUseXml_thenConverted(){
+        RelationalJMapper<User> relationalMapper = new RelationalJMapper<>(User.class,"user_jmapper2.xml");
+        
+        User user = new User(1L,"john@test.com");
+        UserDto1 result1 = relationalMapper.oneToMany(UserDto1.class, user);
+        UserDto2 result2 = relationalMapper.oneToMany(UserDto2.class, user);
+
+        System.out.println(result1);
+        System.out.println(result2);
+        assertEquals(user.getId(), result1.getId());
+        assertEquals(user.getEmail(), result1.getUsername());
+        assertEquals(user.getId(), result2.getId());
+        assertEquals(user.getEmail(), result2.getEmail());         
+    }
+    
+    
+    // ===== API
+    
+    @Test
+    public void givenUser_whenUseApi_thenConverted(){
+        JMapperAPI jmapperApi = new JMapperAPI() 
+        .add(mappedClass(User.class)
+            .add(attribute("id").value("id").targetClasses(UserDto1.class,UserDto2.class))
+            .add(attribute("email").targetAttributes("username","email").targetClasses(UserDto1.class,UserDto2.class)) )
+         ;
+        RelationalJMapper<User> relationalMapper = new RelationalJMapper<>(User.class,jmapperApi);
+        
+        User user = new User(1L,"john@test.com");
+        UserDto1 result1 = relationalMapper.oneToMany(UserDto1.class, user);
+        UserDto2 result2 = relationalMapper.oneToMany(UserDto2.class, user);
+
+        System.out.println(result1);
+        System.out.println(result2);
+        assertEquals(user.getId(), result1.getId());
+        assertEquals(user.getEmail(), result1.getUsername());
+        assertEquals(user.getId(), result2.getId());
+        assertEquals(user.getEmail(), result2.getEmail());            
+    }
+
+}

libraries-data-2/src/test/java/com/baeldung/measurement/WaterTankUnitTest.java

@@ -0,0 +1,86 @@
+package com.baeldung.measurement;
+
+import javax.measure.Quantity;
+import javax.measure.quantity.Area;
+import javax.measure.quantity.Length;
+import javax.measure.quantity.Pressure;
+import javax.measure.quantity.Volume;
+
+import javax.measure.Unit;
+import javax.measure.UnitConverter;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+
+import com.baeldung.measurement.WaterTank;
+
+import tec.units.ri.format.SimpleUnitFormat;
+import tec.units.ri.quantity.Quantities;
+import tec.units.ri.unit.MetricPrefix;
+import static tec.units.ri.unit.Units.*;
+
+public class WaterTankUnitTest {
+
+    @Test
+    public void givenQuantity_whenGetUnitAndConvertValue_thenSuccess() {
+        WaterTank waterTank = new WaterTank();
+        waterTank.setCapacityMeasure(Quantities.getQuantity(9.2, LITRE));
+        assertEquals(LITRE, waterTank.getCapacityMeasure().getUnit());
+
+        Quantity<Volume> waterCapacity = waterTank.getCapacityMeasure();
+        double volumeInLitre = waterCapacity.getValue().doubleValue();
+        assertEquals(9.2, volumeInLitre, 0.0f);
+
+        double volumeInMilliLitre = waterCapacity.to(MetricPrefix.MILLI(LITRE)).getValue().doubleValue();
+        assertEquals(9200.0, volumeInMilliLitre, 0.0f);
+
+        // compilation error
+        // volumeInMilliLitre = waterCapacity.to(MetricPrefix.MILLI(KILOGRAM));
+
+        Unit<Length> Kilometer = MetricPrefix.KILO(METRE);
+
+        // compilation error
+        // Unit<Length> Centimeter = MetricPrefix.CENTI(LITRE);
+    }
+
+    @Test
+    public void givenUnit_whenAlternateUnit_ThenGetAlternateUnit() {
+
+        Unit<Pressure> PASCAL = NEWTON.divide(METRE.pow(2)).alternate("Pa").asType(Pressure.class);
+        assertTrue(SimpleUnitFormat.getInstance().parse("Pa").equals(PASCAL));
+    }
+
+    @Test
+    public void givenUnit_whenProduct_ThenGetProductUnit() {
+        Unit<Area> squareMetre = METRE.multiply(METRE).asType(Area.class);
+        Quantity<Length> line = Quantities.getQuantity(2, METRE);
+        assertEquals(line.multiply(line).getUnit(), squareMetre);
+    }
+
+    @Test
+    public void givenMeters_whenConvertToKilometer_ThenConverted() {
+        double distanceInMeters = 50.0;
+        UnitConverter metreToKilometre = METRE.getConverterTo(MetricPrefix.KILO(METRE));
+        double distanceInKilometers = metreToKilometre.convert(distanceInMeters);
+        assertEquals(0.05, distanceInKilometers, 0.00f);
+    }
+
+    @Test
+    public void givenSymbol_WhenCompareToSystemUnit_ThenSuccess() {
+        assertTrue(SimpleUnitFormat.getInstance().parse("kW").equals(MetricPrefix.KILO(WATT)));
+        assertTrue(SimpleUnitFormat.getInstance().parse("ms").equals(SECOND.divide(1000)));
+    }
+
+    @Test
+    public void givenUnits_WhenAdd_ThenSuccess() {
+        Quantity<Length> total = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, METRE));
+        assertEquals(total.getValue().intValue(), 5);
+
+        // compilation error
+        // Quantity<Length> total = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, LITRE));
+
+        Quantity<Length> totalKm = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, MetricPrefix.KILO(METRE)));
+        assertEquals(totalKm.getValue().intValue(), 3002);
+    }
+}