tester.method = method;
        method.invoke(tester, new Object[] {null});
      }
    }
  }

  private Type getOnlyParameterType() {
    assertThat(method.getGenericParameterTypes()).hasLength(1);
    return method.getGenericParameterTypes()[0];
  }

  @SuppressWarnings({"rawtypes", "unchecked"})
  private static Type getSupertype(Type type, Class<?> superclass) {
    Class rawType = superclass;