Mock HttpClient using Moq

Question

I like the unit test class that uses HttpClient. We entered an object HttpClientin the constructor of the class.

public class ClassA : IClassA
{
    private readonly HttpClient _httpClient;

    public ClassA(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<HttpResponseMessage> SendRequest(SomeObject someObject)
    {
        //Do some stuff

        var request = new HttpRequestMessage(HttpMethod.Post, "http://some-domain.in");

        //Build the request

        var response = await _httpClient.SendAsync(request);

        return response;
    }
}

Now we like the unit test method ClassA.SendRequest. We use Ms Testfor unit testing and Moqfor ridicule.

When we tried to mock HttpClient, he throws out NotSupportedException.

[TestMethod]
public async Task SendRequestAsync_Test()
{
    var mockHttpClient = new Mock<HttpClient>();

    mockHttpClient.Setup(
        m => m.SendAsync(It.IsAny<HttpRequestMessage>()))
    .Returns(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)));
}

How can we solve this problem?

Answer 1

This overload method is not virtual, so it cannot be overridden by Moq.

public Task<HttpResponseMessage> SendAsync(HttpRequestMessage request);

That's why he throws NotSupportedException

The virtual method you are looking for is a method

public virtual Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken);

HttpClient , .

, .

.

public class DelegatingHandlerStub : DelegatingHandler {
    private readonly Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> _handlerFunc;
    public DelegatingHandlerStub() {
        _handlerFunc = (request, cancellationToken) => Task.FromResult(request.CreateResponse(HttpStatusCode.OK));
    }

    public DelegatingHandlerStub(Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> handlerFunc) {
        _handlerFunc = handlerFunc;
    }

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) {
        return _handlerFunc(request, cancellationToken);
    }
}

, , . .

, -

public async Task _SendRequestAsync_Test() {
    //Arrange           
    var handlerStub = new DelegatingHandlerStub();
    var client = new HttpClient(handlerStub);
    var sut = new ClassA(client);
    var obj = new SomeObject() {
        //Populate
    };

    //Act
    var response = await sut.SendRequest(obj);

    //Assert
    Assert.IsNotNull(response);
    Assert.IsTrue(response.IsSuccessStatusCode);
}

Answer 2

Propper, HttpClient, , , dotnet. HTTP--, , URL- , , HTTP-, mocks, . WireMock.net , .

, http://some-domain.in - , :

var server = FluentMockServer.Start(/*server and port can be setup here*/);
server.Given(
      Request.Create()
      .WithPath("/").UsingPost()
   )
   .RespondWith(
       Response.Create()
       .WithStatusCode(200)
       .WithHeader("Content-Type", "application/json")
       .WithBody("{'attr':'value'}")
   );

wiremock .