在ASP.NET Core Controller中模拟HttpRequest

Question

I'm building a Web API in ASP.NET Core, and I want to unit test the controllers.

I inject an interface for data access, that I can easily mock. But the controller has to check the headers in the Request for a token, and that Request doesn't seem to exist when I simply instantiate the controller myself, and it is also get-only, so I can't even manually set it. I found lots of examples to mock an ApiController, but that isn't .NET core. Also many tutorials and examples of how to unit test .net core controllers, but none actually used the HttpRequest.

I built an MCVE to demonstrate this:

[Produces("application/json")]
[Route("api/Players")]
public class PlayersController : Controller
{
    private IAccessor accessor;

    public PlayersController(IAccessor ac = null):base()
    {
        accessor = ac ?? AccessorFactory.GetAccessor();
    }

    /// <summary>
    /// Get all players. Must be logged in.
    /// </summary>
    /// <returns>Ok or Unauthorized.</returns>
    [HttpGet]
    public IActionResult Get()
    {
        Player client = accessor.GetLoggedInPlayer(Request.Headers["token"]); // NRE here because Request is null
        if (client == null) return Unauthorized();
        return Ok(accessor.GetAllPlayers());

    }
}    

I'm using Moq and MSTest in my test project, and inject a mocked IAccessor. How do I inject the Request, or initialize it with the controller? I guess my last resort would be reflection, but I really want to avoid that.

Answer 1

When creating an instance of the controller under test, make sure to assign a HttpContext that contains the required dependencies for the test to be exercised to completion.

You could try mocking a HttpContext and providing that to the controller or just use DefaultHttpContext provided by the framework

//Arrange
var mockedAccessor = new Mock<IAccessor>();
//...setup mockedAccessor behavior

//...

var httpContext = new DefaultHttpContext(); // or mock a `HttpContext`
httpContext.Request.Headers["token"] = "fake_token_here"; //Set header
 //Controller needs a controller context 
var controllerContext = new ControllerContext() {
    HttpContext = httpContext,
};
//assign context to controller
var controller = new PlayersController (mockedAccessor.Object){
    ControllerContext = controllerContext,
};

//Act
var result = controller.Get();

//...

The above assumes you already know how to mock the controller dependencies like IAccessor and was meant to demonstrate how to provide framework specific dependencies needed for the test.