Demonstrates how a simple test runner can work using annotations and reflection.

TestRunner.java

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;

public class TestRunner {
    public static void main(String[] args) {

        System.out.println("Testing...");

        Class<TestClass> testClass = TestClass.class;
        System.out.println("Test class: " + testClass.getName());
        if (testClass.isAnnotationPresent(TestInfo.class)) {
            TestInfo info = testClass.getAnnotation(TestInfo.class);
            System.out.println("Created by: " + info.createdBy());
        }

        for (Method method : testClass.getDeclaredMethods()) {
            if (method.isAnnotationPresent(Test.class)) {
                System.out.println("Test: " + method.getName());
                Test test = method.getAnnotation(Test.class);
                if (test.enabled()) {
                    try {
                        method.invoke(testClass.newInstance());
                        System.out.println("\tSuccess");
                    } catch (Throwable ex) {
                        Throwable cause = ex.getCause();
                        if (cause instanceof TestFailureException) {
                            System.out.println("\tFail: " + cause.getMessage());
                        } else {
                            System.out.println("\tError: " + cause.getMessage());
                        }
                    }
                } else {
                    System.out.println("\tSkip");
                }
            }
        }
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@interface TestInfo {
    String createdBy() default "Anonymous";
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@interface Test {
    boolean enabled() default true;
}

@TestInfo (
        createdBy = "Anders Sigfridsson"
)
class TestClass {

    @Test
    void test1() {
        Assert.assertTrue(true);
    }

    @Test
    void test2() {
        Assert.assertTrue(true);
        throw new IllegalArgumentException("Something always goes wrong here!");
    }

    @Test
    void test3() {
        Assert.assertTrue(false);
    }

    @Test(enabled = false)
    void test4() {
        System.out.println("You should not be seeing this line...");
    }

    @Test
    void test5() {
        Assert.assertTrue(true);
    }
}

class Assert {
    static void assertTrue(boolean value) throws TestFailureException {
        if (value != true) {
            throw new TestFailureException("Expected value to be true");
        }
    }
}

class TestFailureException extends RuntimeException {
    TestFailureException(String message) {
        super(message);
    }
}