}

  public void testNulls() throws Exception {
    NullPointerTester tester = new NullPointerTester();

    tester.testConstructors(PatternFilenameFilter.class, Visibility.PACKAGE);
    tester.testStaticMethods(PatternFilenameFilter.class, Visibility.PACKAGE); // currently none

    // The reason that we skip this method is discussed in a comment on the method.

  /**
   * Runs {@link #testMethod} on every static method of class {@code c} that has at least {@code
   * minimalVisibility}, including those "inherited" from superclasses of the same package.
   */
  public void testStaticMethods(Class<?> c, Visibility minimalVisibility) {
    for (Method method : minimalVisibility.getStaticMethods(c)) {
      if (!isIgnored(method)) {
        testMethod(null, method);
      }
    }
  }

  /**

        new NullPointerTester()
            .setDefault(SleepingStopwatch.class, stopwatch)
            .setDefault(int.class, 1)
            .setDefault(double.class, 1.0d);
    tester.testStaticMethods(RateLimiter.class, Visibility.PACKAGE);
    tester.testInstanceMethods(RateLimiter.create(5.0, stopwatch), Visibility.PACKAGE);
  }

  public void testVerySmallDoubleValues() throws Exception {

        new NullPointerTester()
            .setDefault(SleepingStopwatch.class, stopwatch)
            .setDefault(int.class, 1)
            .setDefault(double.class, 1.0d);
    tester.testStaticMethods(RateLimiter.class, Visibility.PACKAGE);
    tester.testInstanceMethods(RateLimiter.create(5.0, stopwatch), Visibility.PACKAGE);
  }

  public void testVerySmallDoubleValues() throws Exception {

          FactoryMethodReturnsNullException {
    if (!Modifier.isAbstract(cls.getModifiers())) {
      nullPointerTester.testConstructors(cls, visibility);
    }
    nullPointerTester.testStaticMethods(cls, visibility);
    if (hasInstanceMethodToTestNulls(cls, visibility)) {
      Object instance = instantiate(cls);
      if (instance != null) {
        nullPointerTester.testInstanceMethods(instance, visibility);

    shouldFail(instance, Visibility.PROTECTED);
    shouldFail(instance, Visibility.PUBLIC);
  }

  private static void shouldFail(Class<?> cls, Visibility visibility) {
    try {
      new NullPointerTester().testStaticMethods(cls, visibility);
    } catch (AssertionError expected) {
      return;
    }
    fail("Should detect problem in " + cls.getSimpleName());
  }

  private static void shouldFail(Class<?> cls) {

          FactoryMethodReturnsNullException {
    if (!Modifier.isAbstract(cls.getModifiers())) {
      nullPointerTester.testConstructors(cls, visibility);
    }
    nullPointerTester.testStaticMethods(cls, visibility);
    if (hasInstanceMethodToTestNulls(cls, visibility)) {
      Object instance = instantiate(cls);
      if (instance != null) {
        nullPointerTester.testInstanceMethods(instance, visibility);