This leaves the job of displaying or rendering the data to your front-end components. It's considered best practice to put your data logic inside a service that can be shared across the application. Maybe your experience with Angular has been different than mine but I find that the HttpClient is a common dependency in an Angular service. Want to skip the read and get to the code right away? Then click here.Ī common dependency inside an Angular service file is the HttpClient? □ So you can shake the bugs outta your Angular code. That's it.How to test Angular services with the HttpClient. But these will not catch the errors in your communication, for that you will have to do a higher level of testing. That of course does not exclude unit tests, which can still be added. It would make sense to test it together with whatever you are calling. Remember that the HttpClient is an integration point. This is another approach that I have seen. This way you would be able to mock all the methods. In the above I have not taken the approach of wrapping HttpClient in another class with an interface. However you do not have to create a new version of the HttpMessageHandler interface every time. This solution gives the exact same result as the first one. Which means I can now create stubs with different results like in the below: var httpClient = new HttpClient(new HttpMessageHandlerStub(async (request, cancellationToken) => This function will be invoked when SendAsync() is called. In the above my HttpMessageHandlerStub class now has a constructor that takes a function. Return await _sendAsync(request, cancellationToken) Public HttpMessageHandlerStub(Func> sendAsync) However using a function you can easily create a reusable implementation: public class HttpMessageHandlerStub : HttpMessageHandler In the previous example you would have to create a new stub every time you would want a different response. This is the basis on how to mock, fake and stub the HttpClient. Now when any method is called on the httpClient (like GetAsync) in the above, it will return a 200 response with the content "This is a reply". Var httpClient = new HttpClient(new HttpMessageHandlerStub()) //Important part Our new stub is easily invoked by injecting it into the HttpClient and calling a method on it: public static async Task CallHttp() In the above we create our own HttpMessageHandler implementation named HttpMessageHandlerStub. Return await Task.FromResult(responseMessage) Var responseMessage = new HttpResponseMessage(HttpStatusCode.OK)Ĭontent = new StringContent("This is a reply") Protected override async Task SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) Since the MessageHandler is abstract you will have to create your own implementation, which could look like the below: public class HttpMessageHandlerStub : HttpMessageHandler This class can be injected into the HttpClient which let you override any request. Instead the ability to override its functionality is within the abstract class HttpMessageHandler. However there is no interface for HttpClient. Often you would assume that there is an interface which you can mock. Return await httpClient.GetAsync("") //Not a real url. So you have something along the lines of this in your code: var httpClient = new HttpClient()
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