Some services take advantage of the JSONP or XHR module to fetch data instead of the traditional HTTP module. We use the same strategies for testing these services - create a mock back-end, initialize the service and test to see if the request our service made is correct and if the data mocked through the back-end makes its way successfully to the service. Fortunately services that rely on the XHR module are tested exactly the same way as services that use the HTTP module. The only difference is in which class is used to mock the back-end. In services that use the HTTP module, the MockBackend class is used; in those that use XHR, the XHRBackend is used instead. Everything else remains the same.
Unfortunately services that use the JSONP module use a significantly different class for mocking the back-end. The class MockBrowserJsonp is used for this scenario.