How do I unit test web api action method when it returns IHttpActionResult?

Question

Let\'s assume this is my action method

public IHttpActionResult Get(int id)
{
    var status = GetSomething(id);
    if (status)
    {
        return Ok();
          


        

Answer 1

After a few hours of research and trying, I finally figured out how to fully test my Web API 2 methods that return IHttpActionResult and use the OWIN middleware and the default implementation of ASP.NET Identity.

I will be testing the Get() method on the following ApiController:

public class AccountController : ApiController
{
    private ApplicationUserManager _userManager;
    public ApplicationUserManager UserManager => _userManager ?? HttpContext.Current.GetOwinContext().GetUserManager();

    [Route("api/account"), HttpGet]
    public async Task Get()
    {
        var user = await UserManager.FindByIdAsync(User.Identity.GetUserId());
        if (user == null)
        {
            ModelState.AddModelError(ModelStateConstants.Errors, "Account not found! Try logging out and in again.");
            return BadRequest(ModelState);
        }

        var roles = await UserManager.GetRolesAsync(user.Id);

        var accountModel = new AccountViewModel
        {
            FullName = user.FullName,
            Email = user.Email,
            Phone = user.PhoneNumber,
            Organization = user.Organization.Name,
            Role = string.Join(", ", roles)
        };

        return Ok(accountModel);
    }

    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            if (_userManager != null)
            {
                _userManager.Dispose();
                _userManager = null;
            }
        }

        base.Dispose(disposing);
    }
}

Start with a base class that all test classes will inherit from:

public class BaseTest
{
    protected static User CurrentUser;
    protected static IList Roles;

    public BaseTest()
    {
        var email = "unit@test.com";

        CurrentUser = new User
        {
            FullName = "Unit Tester",
            Email = email,
            UserName = email,
            PhoneNumber = "123456",
            Organization = new Organization
            {
                Name = "Test Organization"
            }
        };

        Roles = new List
        {
            "Administrator"
        };
    }

    protected void InitializeApiController(ApiController apiController)
    {
        //Init fake controller Http and Identity data
        var config = new HttpConfiguration();
        var request = new HttpRequestMessage();
        var routeData = new HttpRouteData(new HttpRoute(""));
        apiController.ControllerContext = new HttpControllerContext(config, routeData, request)
        {
            Configuration = config
        };

        apiController.User = new GenericPrincipal(new GenericIdentity(""), new[] { "" });

        //Initialize Mocks
        var appUserMgrMock = GetMockedApplicationUserManager();
        var appSignInMgr = GetMockedApplicationSignInManager(appUserMgrMock);
        var appDbContext = GetMockedApplicationDbContext();

        //Configure HttpContext.Current.GetOwinContext to return mocks
        var owin = new OwinContext();
        owin.Set(appUserMgrMock.Object);
        owin.Set(appSignInMgr.Object);
        owin.Set(appDbContext.Object);

        HttpContext.Current = new HttpContext(new HttpRequest(null, "http://test.com", null), new HttpResponse(null));
        HttpContext.Current.Items["owin.Environment"] = owin.Environment;
    }

    private static Mock GetMockedApplicationSignInManager(Mock appUserMgrMock)
    {
        var authMgr = new Mock();
        var appSignInMgr = new Mock(appUserMgrMock.Object, authMgr.Object);

        return appSignInMgr;
    }

    private Mock GetMockedApplicationUserManager()
    {
        var userStore = new Mock>();
        var appUserMgr = new Mock(userStore.Object);
        appUserMgr.Setup(aum => aum.FindByIdAsync(It.IsAny())).ReturnsAsync(CurrentUser);
        appUserMgr.Setup(aum => aum.GetRolesAsync(It.IsAny())).ReturnsAsync(Roles);

        return appUserMgr;
    }

    private static Mock GetMockedApplicationDbContext()
    {
        var dbContext = new Mock();
        dbContext.Setup(dbc => dbc.Users).Returns(MockedUsersDbSet);

        return dbContext;
    }

    private static IDbSet MockedUsersDbSet()
    {
        var users = new List
        {
            CurrentUser,
            new User
            {
                FullName = "Testguy #1",
                Email = "test@guy1.com",
                UserName = "test@guy1.com",
                PhoneNumber = "123456",
                Organization = new Organization
                {
                    Name = "Test Organization"
                }
            }
        }.AsQueryable();

        var usersMock = new Mock>();
        usersMock.As>().Setup(m => m.Provider).Returns(users.Provider);
        usersMock.As>().Setup(m => m.Expression).Returns(users.Expression);
        usersMock.As>().Setup(m => m.ElementType).Returns(users.ElementType);
        usersMock.As>().Setup(m => m.GetEnumerator()).Returns(users.GetEnumerator);

        return usersMock.Object;
    }
}

The InitializeApiController method contains the meat and potatoes.

Now we can write our tests for AccountController:

public class AccountControllerTests : BaseTest
{
    private readonly AccountController _accountController;

    public AccountControllerTests()
    {
        _accountController = new AccountController();
        InitializeApiController(_accountController);
    }

    [Test]
    public async Task GetShouldReturnOk()
    {
        var result = await _accountController.Get();
        var response = await result.ExecuteAsync(CancellationToken.None);
        Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
    }
}

For everything to work, you'll need to install a bunch of Microsoft.OWIN.* and Microsoft.AspNet.* packages, I'll paste my packages.config here:

The test is very simple, but demonstrates that everything works :-)

Happy testing!