Using the HttpClientInterception to Test Methods That Use a HttpClient
Full source code available here.
In my previous post I showed a way of testing a controller that uses a HttpClient.
I had to mock the HttpMessageHandler pass that to the HttpClient and set a bunch of properties. It works well, but is a bit long winded.
I received a comment from a reader who suggested that I try the JustEat.HttpClientInterception library. It allows you to setup responses to specified requests, and pass these to a HttpClient. Then the HttpClient is passed to the controller.
Here is how the test method looks -
1[Fact]
2public async Task GetTest()
3{
4 //Arrange
5 List<int> myList = new List<int>() {1, 2, 3, 4, 5};
6
7 // setup the interceptor
8 HttpRequestInterceptionBuilder builder = new HttpRequestInterceptionBuilder()
9 .ForHost("localhost.something.com")
10 .ForPath("/v1/numbers")
11 .WithJsonContent(myList);
12
13 // create the HttpClient from the builder
14 // and setup the HttpClientBaseAddress
15 HttpClient client = new HttpClientInterceptorOptions()
16 .Register(builder).CreateHttpClient("http://localhost.something.com/v1/");
17
18 ValuesController controller = new ValuesController(client);
19
20 //Act
21 IActionResult result = await controller.Get();
22
23 //Assert
24 OkObjectResult resultObject = result as OkObjectResult;
25 Assert.NotNull(resultObject);
26
27 List<int> numbers = resultObject.Value as List<int>;
28 Assert.Equal(5, numbers.Count);
29}Briefly, here is the constructor of the values controller. It takes the HttpClient as a parameter, usually passed by dependency injection.
1public class ValuesController : Controller
2{
3 readonly IAsyncPolicy<HttpResponseMessage> _httpRetryPolicy;
4 private readonly HttpClient _httpClient;
5
6 public ValuesController(HttpClient httpClient)
7 {
8 _httpClient = httpClient;
9 }
10 //snip..Full source code available here.