public void ShouldNot_ReturnNullAndShouldCallMethodGetOfIRepository_WhenRequestedDetails() { //arrange var employee = new Person { Id = 1, Role = PersonRole.Employee }; var repository = Substitute.For<IRepository>(); repository.Get<Person>(1).Returns(employee); var employeeController = new EmployeesController(repository, appContext); //act var viewModel = employeeController.Details(1).Model as Person; //assert viewModel.Should().NotBeNull(); repository.Received().Get<Person>(1); }