BAEL-4437 - System Rules (#10047)

Co-authored-by: Jonathan Cook <jcook@sciops.esa.int>
2020-09-17 23:22:49 +02:00
parent 4c39bcd6be
commit f6adcd0cb3
12 changed files with 288 additions and 1 deletions
@@ -0,0 +1,19 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertNull;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ClearSystemProperties;
+
+public class ClearSystemPropertiesWithRuleUnitTest {
+
+    @Rule
+    public final ClearSystemProperties userNameIsClearedRule = new ClearSystemProperties("user.name");
+
+    @Test
+    public void givenClearUsernameProperty_whenGetUserName_thenNull() {
+        assertNull(System.getProperty("user.name"));
+    }
+
+}
@@ -0,0 +1,26 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.restoreSystemProperties;
+import static org.junit.Assert.assertEquals;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+class ProvidesSystemPropertyUnitTest {
+
+    @BeforeAll
+    static void setUpBeforeClass() throws Exception {
+        System.setProperty("log_dir", "/tmp/baeldung/logs");
+    }
+
+    @Test
+    void givenSetSystemProperty_whenGetLogDir_thenLogDirIsProvidedSuccessfully() throws Exception {
+        restoreSystemProperties(() -> {
+            System.setProperty("log_dir", "test/resources");
+            assertEquals("log_dir should be provided", "test/resources", System.getProperty("log_dir"));
+        });
+
+        assertEquals("log_dir should be provided", "/tmp/baeldung/logs", System.getProperty("log_dir"));
+    }
+
+}
@@ -0,0 +1,44 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ProvideSystemProperty;
+
+public class ProvidesSystemPropertyWithRuleUnitTest {
+
+    @Rule
+    public final ProvideSystemProperty providesSystemPropertyRule = new ProvideSystemProperty("log_dir", "test/resources").and("another_property", "another_value");
+
+    @Rule
+    public final ProvideSystemProperty providesSystemPropertyFromFileRule = ProvideSystemProperty.fromResource("/test.properties");
+
+    @BeforeClass
+    public static void setUpBeforeClass() {
+        setLogs();
+    }
+
+    @AfterClass
+    public static void tearDownAfterClass() throws Exception {
+        System.out.println(System.getProperty("log_dir"));
+    }
+
+    @Test
+    public void givenProvideSystemProperty_whenGetLogDir_thenLogDirIsProvidedSuccessfully() {
+        assertEquals("log_dir should be provided", "test/resources", System.getProperty("log_dir"));
+    }
+
+    @Test
+    public void givenProvideSystemPropertyFromFile_whenGetName_thenNameIsProvidedSuccessfully() {
+        assertEquals("name should be provided", "baeldung", System.getProperty("name"));
+        assertEquals("version should be provided", "1.0", System.getProperty("version"));
+    }
+
+    private static void setLogs() {
+        System.setProperty("log_dir", "/tmp/baeldung/logs");
+    }
+
+}
@@ -0,0 +1,24 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.tapSystemErr;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.Test;
+
+class SystemErrPrintlnUnitTest {
+
+    @Test
+    void givenTapSystemErr_whenInvokePrintln_thenOutputIsReturnedSuccessfully() throws Exception {
+
+        String text = tapSystemErr(() -> {
+            printError("An error occurred Baeldung Readers!!");
+        });
+
+        Assert.assertEquals("An error occurred Baeldung Readers!!", text.trim());
+    }
+
+    private void printError(String output) {
+        System.err.println(output);
+    }
+
+}
@@ -0,0 +1,25 @@
+package com.baeldung.systemrules;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.SystemErrRule;
+
+public class SystemErrPrintlnWithRuleUnitTest {
+
+    @Rule
+    public final SystemErrRule systemErrRule = new SystemErrRule().enableLog();
+
+    @Test
+    public void givenSystemErrRule_whenInvokePrintln_thenLogSuccess() {
+        printError("An Error occurred Baeldung Readers!!");
+
+        Assert.assertEquals("An Error occurred Baeldung Readers!!", systemErrRule.getLog()
+            .trim());
+    }
+
+    private void printError(String output) {
+        System.err.println(output);
+    }
+
+}
@@ -0,0 +1,23 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.catchSystemExit;
+
+import org.junit.jupiter.api.Test;
+
+class SystemExitUnitTest {
+
+    @Test
+    void givenCatchSystemExit_whenAppCallsSystemExit_thenStatusIsReturnedSuccessfully() throws Exception {
+        int statusCode = catchSystemExit(() -> {
+            exit();
+        });
+        assertEquals("status code should be 1:", 1, statusCode);
+    }
+
+    private void exit() {
+        System.exit(1);
+    }
+
+}
@@ -0,0 +1,22 @@
+package com.baeldung.systemrules;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ExpectedSystemExit;
+
+public class SystemExitWithRuleUnitTest {
+
+    @Rule
+    public final ExpectedSystemExit exitRule = ExpectedSystemExit.none();
+
+    @Test
+    public void givenSystemExitRule_whenAppCallsSystemExit_thenExitRuleWorkssAsExpected() {
+        exitRule.expectSystemExitWithStatus(1);
+        exit();
+    }
+
+    private void exit() {
+        System.exit(1);
+    }
+
+}
@@ -0,0 +1,27 @@
+package com.baeldung.systemrules;
+
+import static com.github.stefanbirkner.systemlambda.SystemLambda.withTextFromSystemIn;
+import static org.junit.Assert.assertEquals;
+
+import java.util.Scanner;
+
+import org.junit.jupiter.api.Test;
+
+class SystemInUnitTest {
+
+    @Test
+    void givenTwoNames_whenSystemInMock_thenNamesJoinedTogether() throws Exception {
+        withTextFromSystemIn("Jonathan", "Cook").execute(() -> {
+            assertEquals("Names should be concatenated", "Jonathan Cook", getFullname());
+        });
+    }
+
+    private String getFullname() {
+        try (Scanner scanner = new Scanner(System.in)) {
+            String firstName = scanner.next();
+            String surname = scanner.next();
+            return String.join(" ", firstName, surname);
+        }
+    }
+
+}
@@ -0,0 +1,31 @@
+package com.baeldung.systemrules;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Scanner;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.TextFromStandardInputStream;
+import static org.junit.contrib.java.lang.system.TextFromStandardInputStream.emptyStandardInputStream;
+
+public class SystemInWithRuleUnitTest {
+
+    @Rule
+    public final TextFromStandardInputStream systemInMock = emptyStandardInputStream();
+
+    @Test
+    public void givenTwoNames_whenSystemInMock_thenNamesJoinedTogether() {
+        systemInMock.provideLines("Jonathan", "Cook");
+        assertEquals("Names should be concatenated", "Jonathan Cook", getFullname());
+    }
+
+    private String getFullname() {
+        try (Scanner scanner = new Scanner(System.in)) {
+            String firstName = scanner.next();
+            String surname = scanner.next();
+            return String.join(" ", firstName, surname);
+        }
+    }
+
+}