如何使用 nunit 使用 httpclient PostAsync 和 GetAsync 对代码进行单元测试

Question

I have an ApiController where I have 2 calls for getting response from external APis- httpClient.PostAsync and httpClient.GetAsync.

Can i get some suggestions for UnitTesting(Nunit) - httpClient.PostAsync and httpClient.GetAsync interactions.

Code Snippet below-

 [System.Web.Http.RoutePrefix("api/v1/testApi")]
    [System.Web.Http.AllowAnonymous]
    public class TestApiController : ApiController
    {
          //get settings data from config file -TestFetchTokenLogin , TestFetchTokenKey , TestFetchTokenUri etc

        [System.Web.Http.Route("gettestapi")]
        [ValidateAntiForgeryToken]
        public IHttpActionResult GetTestAPI(string param1 = "", string param2 = "", string param3 = "", string param4 = "")
        {
            ApiDataResponse dataResponse;
            var httpClient = new HttpClient(new HttpClientHandler { UseProxy = false });
            try
            {
                List<KeyValuePair<string, string>> fetchTokenrequest = new List<KeyValuePair<string, string>>
                {
                    new KeyValuePair<string, string>("login", TestFetchTokenLogin),
                    new KeyValuePair<string, string>("password", TestFetchTokenKey)
                };
                FormUrlEncodedContent fetchTokenrequestBody = new FormUrlEncodedContent(fetchTokenrequest);
                var fetchTokenResponse = httpClient.PostAsync(TestFetchTokenUri, fetchTokenrequestBody);
                if (fetchTokenResponse != null)
                {
                    var tokenResponse = JToken.Parse(fetchTokenResponse.Result.Content.ReadAsStringAsync().Result);
                    var token = tokenResponse?.SelectToken("access_token")?.ToString();
                    if (!string.IsNullOrWhiteSpace(token))
                    {
                        var apiResponse = httpClient.GetAsync($"{TestFetchDataUri}?restapi.session_key={token}&param1={param1}&param2={param2}&sub_param2={param3}&param4={param4}&OutputFormat=json");
                        var task = apiResponse.Result.Content.ReadAsStringAsync();
                        dataResponse = new ApiDataResponse
                        {
                            Success = true,
                            Response = task.Result
                        };
                        return ResponseMessage(Request.CreateResponse(HttpStatusCode.OK, dataResponse));
                    }
                    dataResponse = new ApiDataResponse
                    {
                        Success = false,
                        Response = "access_token not exists in the response"
                    };
                    return ResponseMessage(Request.CreateResponse(HttpStatusCode.NoContent, dataResponse));
                }
                dataResponse = new ApiDataResponse
                {
                    Success = false,
                    Response = "token response empty or null"
                };
                return ResponseMessage(Request.CreateResponse(HttpStatusCode.InternalServerError, dataResponse));
            }
            catch (Exception ex)
            {
                dataResponse = new ApiDataResponse
                {
                    Success = false,
                    Response = ex.Message
                };
                return ResponseMessage(Request.CreateResponse(HttpStatusCode.InternalServerError, dataResponse));
            }
        }
    }
}

Answer 1

I would suggestion to split of the api functionality and your logic.

Move both http calls to the logic and create the HttpClient in the constructor and don't forget dispose.

Reason for this: 1. you can write route test without implementing all the HttpClient stuff 2. You can test you HttpClient calls (post, get) with an mocked http handler or mock the HttpClient -> both is possible if you inject on of them via the constructor in the logic

Please implement the async - await pattern correct.

I did a quick split - I would handle the logic like this (see below) and call this logic from the api.

public class TestLogic : IDispose {

private HttpClientHandler _Handler;

// I would handle the login and password in a own config object 
public TestLogic(HttpClientHandler handler, Config config )
{
    _Handler = handler ?? throw new ArgumentException(); 
}

public async Task<ApiDataResponse> PostfetchTokenrequestBodyAsync()
{
    List<KeyValuePair<string, string>> fetchTokenrequest = new List<KeyValuePair<string, string>>
    {
        new KeyValuePair<string, string>("login", TestFetchTokenLogin),
        new KeyValuePair<string, string>("password", TestFetchTokenKey)
    };
    FormUrlEncodedContent fetchTokenrequestBody = new FormUrlEncodedContent(fetchTokenrequest);
    var fetchTokenResponse = await httpClient.PostAsync(TestFetchTokenUri, fetchTokenrequestBody).ConfigurationAwait(false);
    fetchTokenResponse.EnsureSuccessStatusCode();

    var tokenResponse = JToken.Parse(await fetchTokenResponse.ReadAsStringAsync().ConfigurationAwait(false));

    var token = tokenResponse?.SelectToken("access_token")?.ToString();

    return tokenResponse;
}

public async Task<ApiDataResponse> GetHinterlandFetchDataUriAsync(string token, ...)
{
    var apiResponse = httpClient.GetAsync($"{HinterlandFetchDataUri}?restapi.session_key={token}&param1={param1}&param2={param2}&sub_param2={param3}&param4={param4}&OutputFormat=json");
    apiResponse.EnsureSuccessStatusCode(); // handle exception 

    var result = await apiResponse.Result.Content.ReadAsStringAsync().ConfigurationAwait(false);

    return = new ApiDataResponse
    {
        Success = true,
        Response = result
    };
}

// implement IDisposable interface correct https://docs.microsoft.com/de-de/dotnet/api/system.idisposable?view=netframework-4.7.2

}