@SuppressWarnings("unused") // used by reflection
  private static class PrivateClassWithPrivateConstructor {
    private PrivateClassWithPrivateConstructor(@Nullable Integer argument) {}
  }

  public void testPrivateClass() {
    NullPointerTester tester = new NullPointerTester();
    for (Constructor<?> constructor :
        PrivateClassWithPrivateConstructor.class.getDeclaredConstructors()) {
      tester.testConstructor(constructor);