Full source code available here.
In this post I’m going to show you how test an action method of controller that uses a HttpClient. When performing this test you want to isolate just the code of the action method for testing, you want to remove the dependency on the HttpClient. I hoped it would be simple, that there would be an IHttpClient, but there is not.
Instead I mocked the HttpMessageHandler, then pass it to the constructor of the HttpClient. The HttpMessageHandler is set to return a list of numbers in response to any request.
The constructor of the controller takes the HttpClient as a parameter, usually passed by dependency injection.
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| public class ValuesController : Controller
{
readonly IAsyncPolicy<HttpResponseMessage> _httpRetryPolicy;
private readonly HttpClient _httpClient;
public ValuesController(HttpClient httpClient)
{
_httpClient = httpClient;
}
//snip..
|
In the test class I mock the HttpMessageHandler, set its SendAsync method to return OK and a list of numbers in response to any request. I then pass the mocked HttpMessageHandler to the constructor of the HttpClient.
Now the HttpClient will return the list of numbers I expect and I my test just tests the code of the action method.
The rest of the test is written as normal.
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| [Fact]
public async Task GetTest()
{
//Arrange
string numberJson= JsonConvert.SerializeObject(new List<int>() { 1, 2, 3, 4, 5 });
var httpMessageHandler = new Mock<HttpMessageHandler>();
httpMessageHandler.Protected()
.Setup<Task<HttpResponseMessage>>("SendAsync", ItExpr.IsAny<HttpRequestMessage>(),
ItExpr.IsAny<CancellationToken>())
.Returns(Task.FromResult(new HttpResponseMessage
{
StatusCode = HttpStatusCode.OK,
Content = new StringContent(numberJson, Encoding.UTF8, "application/json"),
}));
HttpClient httpClient = new HttpClient(httpMessageHandler.Object);
httpClient.BaseAddress = new Uri(@"http://localhost:63781/v1/");
httpClient.DefaultRequestHeaders.Accept.Clear();
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
ValuesController controller = new ValuesController(httpClient);
//Act
IActionResult result = await controller.Get();
//Assert
OkObjectResult resultObject = result as OkObjectResult;
Assert.NotNull(resultObject);
List<int> numbers = resultObject.Value as List<int>;
Assert.Equal(5, numbers.Count);
}
|
Full source code available here.