source: class InputValidatorTest {
  
    @Test
    public void testIsValidClusterNamespaceWithInCorrectInput() throws Exception {
  
target:     String someInvalidInput = "中文123";
      assertFalse(InputValidator.isValidClusterNamespace(someInvalidInput));
  
      String anotherInvalidInput = "123@#{}";
      assertFalse(InputValidator.isValidClusterNamespace(anotherInvalidInput));
    }
  
  }