如何对 Refit ApiResponse 进行单元测试<T> ?

Question

I'm using refit to call APIs and the response is wrapped in ApiResonse<T> . I can mock the refit call that returns a mocked ApiResponse<T> and assert. Everything works as it should except I'm not sure how I can test the api call that returns an exception.

[Get("/customer/{id}")]
Task<ApiResponse<Customer>> GetCustomer(int id);

It seems if ApiResponse<T> is used Refit wraps all the exceptions that happens inside the request into ApiException and attaches to ApiResponse<T> . If Task<T> is used instead, catching the ApiException is the responsibility of the caller.

I created the ApiException with ApiException.Create() but not sure where to put that in the ApiResponse<T> . The last parameter to the Create() method is ApiException but the exception I create and set doesn't show up in the ApiResponse at all and therefore can't test.

var apiResponse = new ApiResponse<Customer>(
    new HttpResponseMessage(BadRequest),
    null,
    null,
    await ApiException.Create(,,,Exception("Something bad happened inside the api")
 );

I can't get the Something bad happened... message in the unit test but just the 'Bad Request' message. Am I unit testing the ApiResponse in refit right? Any help is greatly appreciated. Thanks

Answer 1

I don't know Refit, but according to their docs I'd expect the following two options:

Return ApiResponse<Customer>

Let's take a look at your code (which is not correct C#, by the way - please provide correctly working code):

var apiResponse = new ApiResponse<Customer>(
    new HttpResponseMessage(BadRequest),
    null,
    null,
    await ApiException.Create(,,,Exception("Something bad happened inside the api")
 );

When executing this code, Refit is instructed to return exactly what you ask for: return HTTP 500 with the following inner exception .

So I'd expect you'll find Something bad happened inside the api inside apiResponse.Error , but no exception will be thrown.

Throw ApiException

Since ApiException derives from System.Exception , you can replace this

var apiResponse = new ApiResponse<Customer>(
    new HttpResponseMessage(BadRequest),
    null,
    null,
    await ApiException.Create(,,,Exception("Something bad happened inside the api")
 );

by

throw await ApiException.Create("Something bad happened inside the api", message, method, response, settings);

Now you can catch your exception inside your unit test.