Added support for JUnit 4, JUnit 5 and hybrid JUnit4/5 situations

build.gradle

@@ -129,6 +129,39 @@ publishing {
                     'Hamcrest Library',
                     'A library of Hamcrest matchers - deprecated, please use "hamcrest" instead')
         }
+
+        def hamcrestJUnit5TestsProject = project(':hamcrest-junit5-tests')
+        hamcrestJUnit5Tests(MavenPublication) {
+            from hamcrestJUnit5TestsProject.components.java
+            artifactId hamcrestJUnit5TestsProject.name
+            artifact hamcrestJUnit5TestsProject.sourcesJar
+            artifact hamcrestJUnit5TestsProject.javadocJar
+            pom pomConfigurationFor(
+                    'Hamcrest JUnit 5 Tests',
+                    'A test suite for Hamcrest assumptions using JUnit 5')
+        }
+
+        def hamcrestJUnit4TestsProject = project(':hamcrest-junit4-tests')
+        hamcrestJUnit4Tests(MavenPublication) {
+            from hamcrestJUnit4TestsProject.components.java
+            artifactId hamcrestJUnit4TestsProject.name
+            artifact hamcrestJUnit4TestsProject.sourcesJar
+            artifact hamcrestJUnit4TestsProject.javadocJar
+            pom pomConfigurationFor(
+                    'Hamcrest JUnit4 Tests',
+                    'A test suite for Hamcrest assumptions using JUnit 4')
+        }
+
+        def hamcrestJUnit4JUnit5TestsProject = project(':hamcrest-junit4-junit5-tests')
+        hamcrestJUnit4JUnit5Tests(MavenPublication) {
+            from hamcrestJUnit4JUnit5TestsProject.components.java
+            artifactId hamcrestJUnit4JUnit5TestsProject.name
+            artifact hamcrestJUnit4JUnit5TestsProject.sourcesJar
+            artifact hamcrestJUnit4JUnit5TestsProject.javadocJar
+            pom pomConfigurationFor(
+                    'Hamcrest Hybrid JUnit 4/JUnit 5 Tests',
+                    'A test suite for Hamcrest assumptions using hybrid JUnit 4/JUnit 5')
+        }
     }
     repositories {
         if (publishToOssrh) {
@@ -150,4 +183,7 @@ signing {
     sign publishing.publications.hamcrest
     sign publishing.publications.hamcrestCore
     sign publishing.publications.hamcrestLibrary
+    sign publishing.publications.hamcrestJUnit5Tests
+    sign publishing.publications.hamcrestJUnit4Tests
+    sign publishing.publications.hamcrestJUnit4JUnit5Tests
 }

hamcrest-junit4-junit5-tests/hamcrest-junit4-junit5-tests.gradle

@@ -0,0 +1,20 @@
+plugins {
+    id 'java'
+}
+
+group 'org.hamcrest'
+version '2.3-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation project(':hamcrest')
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
+    testImplementation 'org.junit.vintage:junit-vintage-engine:5.8.2'
+}
+
+test {
+    useJUnitPlatform()
+}

hamcrest-junit4-junit5-tests/src/test/java/org/hamcrest/JUnit4MatcherAssumeTest.java

@@ -0,0 +1,54 @@
+package org.hamcrest;
+
+import org.junit.Test;
+import org.junit.AssumptionViolatedException;
+import org.opentest4j.TestAbortedException;
+
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+/**
+ * Tests compatibility with JUnit 4 <i>and</i> JUnit 5 on the classpath.
+ * The equivalent test with only JUnit 4 on the classpath is in another module.
+ */
+public class JUnit4MatcherAssumeTest {
+
+    @Test public void
+    assumptionFailsWithMessage() {
+        try {
+            assumeThat("Custom assumption", "a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (AssumptionViolatedException e) {
+            assertEquals("Custom assumption: got: \"a\", expected: a string starting with \"abc\"", e.getMessage());
+        }
+        catch (TestAbortedException e) {
+            throw new AssertionError("Illegal JUnit 5 assumption", e);
+        }
+    }
+
+    @Test public void
+    assumptionFailsWithDefaultMessage() {
+        try {
+            assumeThat("a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (AssumptionViolatedException e) {
+            assertEquals(": got: \"a\", expected: a string starting with \"abc\"", e.getMessage());
+        }
+        catch (TestAbortedException e) {
+            throw new AssertionError("Illegal JUnit 5 assumption", e);
+        }
+    }
+
+    @Test public void
+    assumptionSucceeds() {
+        try {
+            assumeThat("xyz", startsWith("xy"));
+        } catch (TestAbortedException e) {
+            throw new AssertionError("Illegal JUnit 5 assumption", e);
+        }
+    }
+}

hamcrest-junit4-junit5-tests/src/test/java/org/hamcrest/JUnit5MatcherAssumeTest.java

@@ -0,0 +1,62 @@
+package org.hamcrest;
+
+import org.junit.AssumptionViolatedException;
+import org.junit.jupiter.api.Test;
+import org.opentest4j.TestAbortedException;
+
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+/**
+ * Tests compatibility with JUnit 5 with JUnit 4 <i>and</i> JUnit 5 on the classpath.
+ * The equivalent test with only JUnit 4 on the classpath is in another module.
+ */
+class JUnit5MatcherAssumeTest {
+
+    @Test
+    void
+    assumptionFailsWithMessage() {
+        try {
+            assumeThat("Custom assumption", "a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed: Custom assumption", e.getMessage());
+        }
+        catch (AssumptionViolatedException e) {
+            // If we don't catch JUnit 4 exceptions here, then this test will result in a false positive, or actually
+            // a false ignored test.
+            throw new AssertionError("Illegal JUnit 4 assumption", e);
+        }
+    }
+
+    @Test void
+    assumptionFailsWithDefaultMessage() {
+        try {
+            assumeThat("a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed", e.getMessage());
+        }
+        catch (AssumptionViolatedException e) {
+            // If we don't catch JUnit 4 exceptions here, then this test will result in a false positive, or actually
+            // a false ignored test.
+            throw new AssertionError("Illegal JUnit 4 assumption", e);
+        }
+    }
+
+    @Test void
+    assumptionSucceeds() {
+        try {
+            assumeThat("xyz", startsWith("xy"));
+        }
+        catch (AssumptionViolatedException e) {
+            // If we don't catch JUnit 4 exceptions here, then this test will result in a false positive, or actually
+            // a false ignored test.
+            throw new AssertionError("Illegal JUnit 4 assumption", e);
+        }
+    }
+}

hamcrest-junit4-junit5-tests/src/test/java/org/hamcrest/MatcherAssumeTest.java

@@ -0,0 +1,39 @@
+package org.hamcrest;
+
+import org.junit.AssumptionViolatedException;
+import org.junit.jupiter.api.Test;
+import org.opentest4j.TestAbortedException;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class MatcherAssumeTest {
+
+    @Test
+    void assumptionFailsWithAssertionErrorWhenNoJUnitInStackTrace() throws Throwable {
+        // Run the assumption on a separate thread to make sure it has JUnit 4 nor JUnit 5 in its stack trace.
+        ExecutorService executor = newSingleThreadExecutor();
+        try {
+            try {
+                executor.submit(new Runnable() {
+
+                    @Override
+                    public void run() {
+                        assumeThat(1, is(2));
+                    }
+                }).get();
+                fail("Expected " + ExecutionException.class);
+            } catch (ExecutionException expected) {
+                throw expected.getCause();
+            }
+        } catch (AssertionError expected) {
+        } catch (TestAbortedException | AssumptionViolatedException e) {
+            throw new AssertionError(e);
+        }
+    }
+}

hamcrest-junit4-tests/hamcrest-junit4-tests.gradle

@@ -0,0 +1,17 @@
+dependencies {
+    testImplementation project(':hamcrest')
+    testImplementation(group: 'junit', name: 'junit', version: '4.13.2') {
+        transitive = false
+    }
+}
+
+jar {
+    manifest {
+        attributes 'Implementation-Title': project.name,
+                'Implementation-Vendor': 'hamcrest.org',
+                'Implementation-Version': version,
+                'Automatic-Module-Name': 'org.hamcrest.junit4-tests'
+    }
+}
+
+javadoc.title = "Hamcrest JUnit 4 Tests $version"

hamcrest-junit4-tests/src/test/java/org/hamcrest/JUnit4MatcherAssumeTest.java

@@ -0,0 +1,43 @@
+package org.hamcrest;
+
+import org.junit.Test;
+import org.junit.AssumptionViolatedException;
+
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+/**
+ * Tests compatibility with JUnit 4 with only JUnit 4 on the classpath.
+ * The equivalent test with JUnit 4 <i>and</i> JUnit 5 on the classpath is in another module.
+ */
+public class JUnit4MatcherAssumeTest {
+
+    @Test public void
+    assumptionFailsWithMessage() {
+        try {
+            assumeThat("Custom assumption", "a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (AssumptionViolatedException e) {
+            assertEquals("Custom assumption: got: \"a\", expected: a string starting with \"abc\"", e.getMessage());
+        }
+    }
+
+    @Test public void
+    assumptionFailsWithDefaultMessage() {
+        try {
+            assumeThat("a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (AssumptionViolatedException e) {
+            assertEquals(": got: \"a\", expected: a string starting with \"abc\"", e.getMessage());
+        }
+    }
+
+    @Test public void
+    assumptionSucceeds() {
+        assumeThat("xyz", startsWith("xy"));
+    }
+}

hamcrest-junit5-tests/hamcrest-junit5-tests.gradle

@@ -0,0 +1,21 @@
+dependencies {
+    api project(':hamcrest')
+    api 'org.opentest4j:opentest4j:1.2.0'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
+}
+
+jar {
+    manifest {
+        attributes 'Implementation-Title': project.name,
+                'Implementation-Vendor': 'hamcrest.org',
+                'Implementation-Version': version,
+                'Automatic-Module-Name': 'org.hamcrest.junit5-tests'
+    }
+}
+
+test {
+    useJUnitPlatform()
+}
+
+javadoc.title = "Hamcrest JUnit 5 Tests $version"

hamcrest-junit5-tests/src/test/java/org/hamcrest/JUnit5MatcherAssumeTest.java

@@ -0,0 +1,44 @@
+package org.hamcrest;
+
+import org.junit.jupiter.api.Test;
+import org.opentest4j.TestAbortedException;
+
+import static org.hamcrest.MatcherAssume.assumeThat;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+/**
+ * Tests compatibility with JUnit 5 with only JUnit 5 on the classpath.
+ * The equivalent test with JUnit 4 <i>and</i> JUnit 5 on the classpath is in another module.
+ */
+class JUnit5MatcherAssumeTest {
+
+    @Test
+    void
+    assumptionFailsWithMessage() {
+        try {
+            assumeThat("Custom assumption", "a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed: Custom assumption", e.getMessage());
+        }
+    }
+
+    @Test void
+    assumptionFailsWithDefaultMessage() {
+        try {
+            assumeThat("a", startsWith("abc"));
+            fail("should have failed");
+        }
+        catch (TestAbortedException e) {
+            assertEquals("Assumption failed", e.getMessage());
+        }
+    }
+
+    @Test void
+    assumptionSucceeds() {
+        assumeThat("xyz", startsWith("xy"));
+    }
+}

hamcrest/hamcrest.gradle

@@ -3,8 +3,9 @@ apply plugin: 'osgi'
 version = rootProject.version
 
 dependencies {
-    api 'org.opentest4j:opentest4j:1.2.0'
-    testImplementation(group: 'junit', name: 'junit', version: '4.13') {
+    compileOnly 'org.junit.jupiter:junit-jupiter-api:5.8.2'
+    compileOnly 'junit:junit:4.13.2'
+    testImplementation(group: 'junit', name: 'junit', version: '4.13.2') {
         transitive = false
     }
 }