private static boolean containsTests()

in src/main/org/apache/tools/ant/taskdefs/optional/junit/JUnitTestRunner.java [588:681]

• 64 lines of code
• 29 McCabe index (conditional complexity)

    private static boolean containsTests(final Class<?> testClass, final boolean isJUnit4) {
        Class<? extends Annotation> testAnnotation = null;
        Class<? extends Annotation> suiteAnnotation = null;
        Class<? extends Annotation> runWithAnnotation = null;

        try {
            testAnnotation =
                Class.forName("org.junit.Test").asSubclass(Annotation.class);
        } catch (final ClassNotFoundException e) {
            if (isJUnit4) {
                // odd - we think we're JUnit4 but don't support the test annotation. We therefore can't have any tests!
                return false;
            }
            // else... we're a JUnit3 test and don't need the annotation
        }

        try {
            suiteAnnotation = Class.forName("org.junit.Suite.SuiteClasses")
                .asSubclass(Annotation.class);
        } catch (final ClassNotFoundException ex) {
            // ignore - we don't have this annotation so make sure we don't check for it
        }
        try {
            runWithAnnotation = Class.forName("org.junit.runner.RunWith")
                .asSubclass(Annotation.class);
        } catch (final ClassNotFoundException ex) {
            // also ignore as this annotation doesn't exist so tests can't use it
        }

        if (!isJUnit4 && !TestCase.class.isAssignableFrom(testClass)) {
            //a test we think is JUnit3 but does not extend TestCase. Can't really be a test.
            return false;
        }

        // check if we have any inner classes that contain suitable test methods
        for (final Class<?> innerClass : testClass.getDeclaredClasses()) {
            if (containsTests(innerClass, isJUnit4) || containsTests(innerClass, !isJUnit4)) {
                return true;
            }
        }

        if (Modifier.isAbstract(testClass.getModifiers())
                || Modifier.isInterface(testClass.getModifiers())) {
            // can't instantiate class and no inner classes are tests either
            return false;
        }

        if (isJUnit4) {
            if (suiteAnnotation != null && testClass.getAnnotation(suiteAnnotation) != null) {
                // class is marked as a suite. Let JUnit try and work its magic on it.
                return true;
            }
            if (runWithAnnotation != null && testClass.getAnnotation(runWithAnnotation) != null) {
                /* Class is marked with @RunWith. If this class is badly written (no test methods,
                 * multiple constructors, private constructor etc) then the class is automatically
                 * run and fails in the IDEs I've tried... so I'm happy handing the class to JUnit
                 * to try and run, and let JUnit report a failure if a bad test case is provided.
                 * Trying to do anything else is likely to result in us filtering out cases that
                 * could be valid for future versions of JUnit so would just increase future
                 * maintenance work.
                 */
                return true;
            }
        }

        for (final Method m : testClass.getMethods()) {
            if (isJUnit4) {
                // check if suspected JUnit4 classes have methods with @Test annotation
                if (m.getAnnotation(testAnnotation) != null) {
                    return true;
                }
            } else {
                // check if JUnit3 class have public or protected no-args methods starting with
                // names starting with test
                if (m.getName().startsWith("test")
                    && m.getParameterTypes().length == 0
                    && (Modifier.isProtected(m.getModifiers())
                        || Modifier.isPublic(m.getModifiers()))) {
                    return true;
                }
            }
            // check if JUnit3 or JUnit4 test have a public or protected, static,
            // no-args 'suite' method
            if ("suite".equals(m.getName()) && m.getParameterTypes().length == 0
                && (Modifier.isProtected(m.getModifiers())
                    || Modifier.isPublic(m.getModifiers()))
                && Modifier.isStatic(m.getModifiers())) {
                return true;
            }
        }

        // no test methods found
        return false;
    }