@Test
public void testGetPropertyDiff() throws IOException {

  final Props oldProps = new Props();
  final Props newProps1 = new Props();
  oldProps.put("a", "a_value1");
  oldProps.put("b", "b_value1");
  newProps1.put("b", "b_value2");
  final String message1 = PropsUtils.getPropertyDiff(oldProps, newProps1);
  Assert.assertEquals(message1,
      "Deleted Properties: [ a, a_value1], \nModified Properties: [ b, b_value1-->b_value2], ");
  final Props newProps2 = new Props();
  newProps2.put("a", "a_value1");
  newProps2.put("b", "b_value1");
  newProps2.put("c", "c_value1");
  final String message2 = PropsUtils.getPropertyDiff(oldProps, newProps2);
  Assert.assertEquals(message2, "Newly created Properties: [ c, c_value1], \n");
  final Props newProps3 = new Props();
  newProps3.put("b", "b_value1");
  newProps3.put("c", "a_value1");
  final String message3 = PropsUtils.getPropertyDiff(oldProps, newProps3);
  Assert.assertEquals(message3,
      "Newly created Properties: [ c, a_value1], \nDeleted Properties: [ a, a_value1], \n");
}