Merge pull request #7561 from JonCook/master

BAEL-2947 - Guide to Junit 4 Rules

testing-modules/junit-4/pom.xml

@@ -0,0 +1,18 @@
+<?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>
+
+</project>

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/rules/MessageLogger.java

@@ -0,0 +1,34 @@
+package com.baeldung.rules;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MessageLogger implements TestRule {
+
+    private static final Logger LOG = LoggerFactory.getLogger(MessageLogger.class);
+
+    private String message;
+
+    public MessageLogger(String message) {
+        this.message = message;
+    }
+
+    @Override
+    public Statement apply(final Statement base, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                try {
+                    LOG.info("Starting: {}", message);
+                    base.evaluate();
+                } finally {
+                    LOG.info("Finished: {}", message);
+                }
+            }
+        };
+    }
+
+}

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

@@ -0,0 +1,21 @@
+package com.baeldung.rules;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.RuleChain;
+
+public class RuleChainUnitTest {
+
+    @Rule
+    public RuleChain chain = RuleChain.outerRule(new MessageLogger("First rule"))
+        .around(new MessageLogger("Second rule"))
+        .around(new MessageLogger("Third rule"));
+
+    @Test
+    public void givenRuleChain_whenTestRuns_thenChainOrderApplied() {
+        assertTrue(true);
+    }
+
+}

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

@@ -0,0 +1,88 @@
+package com.baeldung.rules;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.isA;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Ignore;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.DisableOnDebug;
+import org.junit.rules.ErrorCollector;
+import org.junit.rules.ExpectedException;
+import org.junit.rules.TemporaryFolder;
+import org.junit.rules.TestName;
+import org.junit.rules.Timeout;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class RulesUnitTest {
+
+    private static final Logger LOG = LoggerFactory.getLogger(RulesUnitTest.class);
+
+    @Rule
+    public TemporaryFolder tmpFolder = new TemporaryFolder();
+
+    @Rule
+    public final ExpectedException thrown = ExpectedException.none();
+
+    @Rule
+    public TestName name = new TestName();
+
+    @Rule
+    public Timeout globalTimeout = Timeout.seconds(10);
+
+    @Rule
+    public final ErrorCollector errorCollector = new ErrorCollector();
+    
+    @Rule
+    public DisableOnDebug disableTimeout = new DisableOnDebug(Timeout.seconds(30));
+    
+    @Rule
+    public TestMethodNameLogger testLogger = new TestMethodNameLogger();
+
+    @Test
+    public void givenTempFolderRule_whenNewFile_thenFileIsCreated() throws IOException {
+        File testFile = tmpFolder.newFile("test-file.txt");
+
+        assertTrue("The file should have been created: ", testFile.isFile());
+        assertEquals("Temp folder and test file should match: ", tmpFolder.getRoot(), testFile.getParentFile());
+    }
+
+    @Test
+    public void givenIllegalArgument_whenExceptionThrown_thenMessageAndCauseMatches() {
+        thrown.expect(IllegalArgumentException.class);
+        thrown.expectCause(isA(NullPointerException.class));
+        thrown.expectMessage("This is illegal");
+
+        throw new IllegalArgumentException("This is illegal", new NullPointerException());
+    }
+
+    @Test
+    public void givenAddition_whenPrintingTestName_thenTestNameIsDisplayed() {
+        LOG.info("Executing: {}", name.getMethodName());
+        assertEquals("givenAddition_whenPrintingTestName_thenTestNameIsDisplayed", name.getMethodName());
+    }
+
+    @Ignore
+    @Test
+    public void givenLongRunningTest_whenTimout_thenTestFails() throws InterruptedException {
+        TimeUnit.SECONDS.sleep(20);
+    }
+
+    @Ignore
+    @Test
+    public void givenMultipleErrors_whenTestRuns_thenCollectorReportsErrors() {
+        errorCollector.addError(new Throwable("First thing went wrong!"));
+        errorCollector.addError(new Throwable("Another thing went wrong!"));
+
+        errorCollector.checkThat("Hello World", not(containsString("ERROR!")));
+    }
+
+}

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

@@ -0,0 +1,32 @@
+package com.baeldung.rules;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class TestMethodNameLogger implements TestRule {
+
+    private static final Logger LOG = LoggerFactory.getLogger(TestMethodNameLogger.class);
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        logInfo("Before test", description);
+        try {
+            return new Statement() {
+                @Override
+                public void evaluate() throws Throwable {
+                    base.evaluate();
+                }
+            };
+        } finally {
+            logInfo("After test", description);
+        }
+    }
+
+    private void logInfo(String msg, Description description) {
+        LOG.info(msg + description.getMethodName());
+    }
+
+}

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

@@ -0,0 +1,30 @@
+package com.baeldung.rules;
+
+import static org.junit.Assert.assertFalse;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Verifier;
+
+public class VerifierRuleUnitTest {
+
+    private List<String> messageLog = new ArrayList<String>();
+
+    @Rule
+    public Verifier verifier = new Verifier() {
+        @Override
+        public void verify() {
+            assertFalse("Message Log is not Empty!", messageLog.isEmpty());
+        }
+    };
+
+    @Test
+    public void givenNewMessage_whenVerified_thenMessageLogNotEmpty() {
+        // ...
+        messageLog.add("There is a new message!");
+    }
+
+}

testing-modules/pom.xml

@@ -37,5 +37,6 @@
         <module>easymock</module>
         <module>junit-5-advanced</module>
         <module>xmlunit-2</module>
+        <module>junit-4</module>
     </modules>
 </project>