@Test
public void testCutValueNull() throws ServletException, IOException {

    // set up
    this.testTarget = new AbstractMDCPutFilter() {
        @Override
        protected String getMDCKey(HttpServletRequest request,
                HttpServletResponse response) {
            return "MDCKey";
        }
        @Override
        protected String getMDCValue(HttpServletRequest request,
                HttpServletResponse response) {
            return "MDCValue";
        }
    };
    // assert
    assertThat(testTarget.cutValue(null), is(nullValue()));
}