Moq returns null and BadRequestObjectResult

Question

I'm new to unit testing, and trying to mock postContinent . But gives null and BadRequestObjectResult .

ContinentControllerTests.cs

 public class ContinentControllerTests {
 // RepoMocks
 private readonly Mock<IContinentRepository> _continentRepoMock = new Mock<IContinentRepository>();
 private readonly Mock<ICountryRepository> _countryRepoMock = new Mock<ICountryRepository>();
 private readonly Mock<ICityRepository> _cityRepoMock = new Mock<ICityRepository>();

 // Controller
 private readonly ContinentController _continentController;

     public ContinentControllerTests() {
     _continentServiceMock = new ContinentService(_continentRepoMock.Object);
     _continentController = new ContinentController(new ContinentService(_continentRepoMock.Object), new CountryService(_countryRepoMock.Object), new CityService(_cityRepoMock.Object));
     }
     [Fact]
     public void PostContinent_ValidInput_ReturnsCreateAtAction() {
     // Arrange
     _continentRepoMock
        .Setup(repo => repo.HeeftContinent("Test"))
        .Returns(false);
    _continentRepoMock
       .Setup(repo => repo.BestaatContinent(new Continent("Test", new List<Country>())))
       .Returns(false);
     _continentRepoMock
       .Setup(repo => repo.VoegContinentToe(new Continent("Test", new List<Country>())))
       .Returns(new Continent(1, "Test", new List<Country>()));
     // Act
     var response = _continentController.PostContinent(new ContinentInputDTO { Name = "Test" });

     // Assert
     Assert.IsType<CreatedAtActionResult>(response.Result);
     }
 }

ContinentController.cs

 public class ContinentController : ControllerBase {
     private string _hostURL = $"http://localhost:5000/api/continent";
     private string _riverURL = $"http://localhost:5000/api/river";

     private ContinentService _continentService;
     private CountryService _countryService;
     private CityService _cityService;

     public ContinentController(ContinentService continentService, CountryService countryService, CityService cityService) {
         _continentService = continentService;
         _countryService = countryService;
         _cityService = cityService;
     }

     [HttpPost]
     public ActionResult<ContinentOutputDTO> PostContinent([FromBody] ContinentInputDTO continentDto) {
         try {
             if (_continentService.HeeftContinent(continentDto.Name)) { return BadRequest("Continent naam moet unique zijn!"); }
             var mappedContinent = MapToDomain.MapToContinentDomain(continentDto);
             Continent continent = _continentService.VoegContinentToe(mappedContinent);
             return CreatedAtAction(nameof(GetContinent), new { continentId = continent.Id },
             MapFromDomain.MapFromContinentDomain(_hostURL, continent));
         }
         catch (Exception ex) { return BadRequest(ex.Message); }
     }
 }

ContinentService.cs

public class ContinentService {
     private readonly IContinentRepository _repo;
     public ContinentService(IContinentRepository repo) { _repo = repo;}

      public Continent VoegContinentToe(Continent c) {
         if (c == null) throw new ContinentServiceException("VoegContinentToe : continent is null");
         if (_repo.BestaatContinent(c)) throw new ContinentServiceException("VoegContinentToe : continent bestaat reeds");
         try {return _repo.VoegContinentToe(c);}
         catch (Exception ex) { throw new ContinentServiceException("VoegContinentToe: ", ex);}
    }
}

Error: Message: Assert.IsType() Failure Expected: Microsoft.AspNetCore.Mvc.CreatedAtActionResult Actual: Microsoft.AspNetCore.Mvc.BadRequestObjectResult

Answer 1

The problem is in your Setup function. Reference types are equal only if you have overridden the equals function or if the are the exact same reference.

So by setting it up with the new keyword, it will never match the execution time object.

Try the It.IsAny<T> function from MOQ to verify.

Check the example here: https://documentation.help/Moq/3CF54A74.htm

// Throws an exception for a call to Remove with any string value.
mock.Setup(x => x.Remove(It.IsAny<string>())).Throws(new InvalidOperationException());