public static String substVars(String val, PropertyContainer pc1) {
    return substVars(val, pc1, null);
  }
@Test
  public void testUndefinedValues() {
    String withUndefinedValues = "${axyz}";
    
    String result = OptionHelper.substVars(withUndefinedValues, context);
    assertEquals("axyz"+OptionHelper._IS_UNDEFINED, result);
  }