@Test
public void check_a_patch_can_remove_a_value_2() throws Exception {

    Map<String, String> patch = new HashMap<String, String>() {{
        put("a", "null");
    }};
    PatchUtil.setMap(testObject.getMap(), patch, true);
    assertThat(testObject.getMap()).hasSize(1);
    assertThat(testObject.getMap()).containsEntry("b", "2");
}