@PrepareForTest({XACMLPapServlet.class})

@Test
public void testNegativeGet() {
    // Mock pap servlet
    PowerMockito.mockStatic(XACMLPapServlet.class);
    when(XACMLPapServlet.getPAPEngine()).thenReturn(null);
    MockHttpServletResponse response = new MockHttpServletResponse();
    MetricService.doGetPolicyMetrics(response);
    assertEquals(HttpServletResponse.SC_BAD_REQUEST, response.getStatusCode());
}