TestUtilities.java

import org.junit.jupiter.api.Test;
import org.junit.platform.commons.support.AnnotationSupport;
import org.junit.platform.commons.support.HierarchyTraversalMode;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.List;
import java.util.logging.Logger;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.platform.commons.util.ReflectionUtils.returnsVoid;

public class TestUtilities {

    private static final Logger logger = Logger.getLogger(TestUtilities.class.getName());

    private TestUtilities() {
        throw new AssertionError("static utility class is not intended to be instantiated");
    }

    /**
     * Execute all of the functions and methods in the calling class that are marked with a @Test annotation. This is
     * intended to be invoked once from a static initializer in a class that defines @Test methods or functions.
     *
     * @throws AssertionError if any tests fail
     */
    public static void runTests() {
        // Note that this depends on knowing the stack depth.
        final String callingClass = new Exception().getStackTrace()[1].getClassName();
        try {
            runTests(Class.forName(callingClass));
        } catch (final ClassNotFoundException e) {
            throw new AssertionError(e);
        }
    }

    /**
     * Execute all of the functions and methods in a class that have a @Test annotation. This is intended to be invoked
     * once from a static initializer in a class that defines @Test methods or functions.
     *
     * @param c the Class to test
     * @throws AssertionError if any tests fail
     */
    public static void runTests(final Class c) {
        logger.fine("executing tests for class " + c.getName());
        final List<Method> testMethods = AnnotationSupport.findAnnotatedMethods(c, Test.class,
                HierarchyTraversalMode.TOP_DOWN);
        for (final Method method : testMethods) {
            assertTrue(returnsVoid(method));
            assertEquals(0, method.getParameterCount());
            logger.fine("executing test " + method);
            try {
                final boolean isStatic = Modifier.isStatic(method.getModifiers());
                final Object o = isStatic ? null : c.getDeclaredConstructor().newInstance();
                method.setAccessible(true);
                method.invoke(o, null);
            } catch (final Exception e) {
                throw new AssertionError(e);
            }
        }
    }

}