responseProvider.addHttpRequestMatchingFilter(filter);
final HttpRequestImpl request1 = new HttpRequestImpl();
request1.method(Method.GET);
request1.path("/a/b");
request1.queryParameter("a", "1");
request1.httpMessageHeader("custom", "value");
final HttpResponse response1 = responseProvider.getResponse(request1);
assertNotNull("We expect matcher to be kicked in and provided response.", response1);
assertEquals("We expect custom response.", 201, response1.getHttpCode());