How to test async Task<IActionResult> returning IEnumerable<model> using moq in xunit?

Question

I want to test GetMoviesAsync of my Controller. I don't know where I am doing wrong in my Moq setup. I am getting 0 item from GetMoviesAsync.

What am I doing wrong?

// Api-Controller:

   public interface ICommand
   {
        Task<IEnumerable<Movie>> GetMoviesAsync();
   }

   public class SampleController : ControllerBase
    {
        private readonly ICommand movieCommand;

        public SampleController(ICommand command)
        {
            movieCommand = command;
        }

        [HttpGet]
        public async Task<IActionResult> GetMoviesAsync()
        {
            var movies = await movieCommand.GetMoviesAsync();
            return Ok(movies);
        }
    }

// Unit-Test:

public class SampleControllerTest
    {
        private IEnumerable<Movie> MovieList()
        {
            IList<Movie> movies = new List<Movie>()
            {
                new Movie()
                {
                    ID =1,
                    Title = "Test",
                    ReleaseDate = DateTime.Now,
                    RunningTimeInMinutes = 100
                }
            };
            return movies;
        }

        private SampleController GetSampleController()
        {
            var command = new Mock<ICommand>();

            return new SampleController(command.Object);
        }

        [Fact]
        public async Task GetMovies_Test()
        {
            // Arrange
            var controller = GetSampleController();
            var commadMock = new Mock<ICommand>();
            // How to setup moq here?
            commadMock.Setup(s => s.GetMoviesAsync()).Returns(Task.FromResult<IEnumerable<Movie>>(MovieList())).Verifiable();
            // Act
            var response = await controller.GetMoviesAsync() as OkObjectResult;
            // Problem is here, 
            var li=response.Value as IEnumerable<Movie>;
         }
    }

Answer 1

What am I doing wrong?

Two completely different mocks are being used.

One is used to create the controller

private SampleController GetSampleController()
{
    var command = new Mock<ICommand>();

    return new SampleController(command.Object);
}

and another is being created and setup in the test.

var controller = GetSampleController();
var commadMock = new Mock<ICommand>();
// How to setup moq here?
commadMock.Setup(s => s.GetMoviesAsync()).Returns(Task.FromResult<IEnumerable<Movie>>(MovieList())).Verifiable();

To solve this, use the same mock to get the desired behavior

[Fact]
public async Task GetMovies_Test() {
    // Arrange
    var commadMock = new Mock<ICommand>();
    var controller = new SampleController(commadMock.Object); //<---
    commadMock
        .Setup(_ => _.GetMoviesAsync())
        .ReturnsAsync(MovieList())
        .Verifiable();

    // Act
    var response = await controller.GetMoviesAsync() as OkObjectResult;

    //Assert
    var list = response.Value as IEnumerable<Movie>;

    //...
 }

Note the use of ReturnsAsync to setup the returned Task

Answer 2

It seems that you are not using the correct mock on the Controller. The one that you are using does not have any setup on top of the method GetMoviesAsync

Answer 3

For me helped almost the solution offered by Nkosi but with little difference

[Fact]
public async Task GetMovies_Test() {
    // Arrange
    var commadMock = new Mock<ICommand>();
    var controller = new SampleController(commadMock.Object); //<---
    commadMock
        .Setup(_ => _.GetMoviesAsync())
        .ReturnsAsync(MovieList());

    // Act
    var response = await controller.GetMoviesAsync();

    //Assert
    var returnValue = Assert.IsType<ViewResult>(response);

    var model = returnValue.Model as IEnumerable<Movie>;

    //...
 }