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

    //GIVEN request and response
    given(resp.getWriter()).willReturn(printWriter);
    ProxyServer.setResponseVolatile(true);
    //WHEN
    underTest.doPost(req, resp);
    //THEN
    verify(resp).setContentType("application/json");
    verify(printWriter).write("{\"responseVolatility\":true}");
}