public void GetParameterById_ShouldReturn_NotNull() { // Arrange fakeParametersRepository.Setup(a => a.GetById(1)).Returns(new ParametersModel { Id = 1, Name = "Param", ProductId = 1, UnitId = 1, Value = "W" }); Mock <ICommonRepository> fakeCommonRepository = new Mock <ICommonRepository>(); fakeCommonRepository.Setup(a => a.GetProductsIdNames()).Returns(new Dictionary <int, string> { { 1, "Product name" } }); fakeCommonRepository.Setup(a => a.GetUnitsIdNames()).Returns(new Dictionary <int, string> { { 1, "p." } }); parametersService = new ParametersService(fakeParametersRepository.Object, fakeCommonRepository.Object); ParametersDtoModel parametersModel = null; try { // Act parametersModel = parametersService.GetParameterById(1); } catch (Exception ex) { errorMessage = ex.Message + " | " + ex.StackTrace; } // Assert Assert.IsNotNull(parametersModel, errorMessage); }