@Test
  public void testCEPOperatorValidation() {

    assertFalse(SuggestionCompletionEngine.isCEPOperator("=="));
    assertFalse(SuggestionCompletionEngine.isCEPOperator("!="));
    assertFalse(SuggestionCompletionEngine.isCEPOperator("<"));
    assertFalse(SuggestionCompletionEngine.isCEPOperator(">"));
    assertFalse(SuggestionCompletionEngine.isCEPOperator("<="));
    assertFalse(SuggestionCompletionEngine.isCEPOperator(">="));
    assertFalse(SuggestionCompletionEngine.isCEPOperator("== null"));
    assertFalse(SuggestionCompletionEngine.isCEPOperator("!= null"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("after"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("before"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("coincides"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("during"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("finishes"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("finishedby"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("includes"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("meets"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("metby"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("overlaps"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("overlappedby"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("starts"));
    assertTrue(SuggestionCompletionEngine.isCEPOperator("startedby"));
  }