Testing ASP.NET Core API controller with InMemory

Question

I am trying to test an ASP.NET Core API controller using an InMemory database, instead of a SQL server. I am also using NUnit to write my tests. In my SetUp-method, I create some data and add to my InMemory context, which seems to work fine, but when I try to retrieve the data using my controller, I get null values.

This is part of my controller:

public class PeopleController : ControllerBase
{
    private ApplicationDbContext _context;
    private IMapper _mapper;
    public PeopleController(ApplicationDbContext context, IMapper mapper)
    {
        _context = context;
        _mapper = mapper;
    }

    // GET /api/people
    [HttpGet]
    public IActionResult GetPeople()
    {
        return Ok(_context.People.ToList().Select(_mapper.Map<Person, PersonDto>));
    }
}

And below is part of my test class. When I debug the test, the two Person objects I add to _context have been added correctly, but when I call _controller.GetPeople(), the two objects do not show up, but I get null back. The method works fine "live", using my SQL Server.

[TestFixture]
class PeopleControllerTests
{
    private ApplicationDbContext _context;
    private IMapper _mapper;
    private PeopleController _controller;

    [SetUp]
    public void SetUp()
    {
        _mapper = GenerateConcreteInstance();

        var options = new DbContextOptionsBuilder<ApplicationDbContext>().UseInMemoryDatabase(databaseName: "TestDb").Options;
        _context = new ApplicationDbContext(options);

        _context.People.Add(new Person()
        { Id = 1, Firstname = "XXXXX", Lastname = "XXXXXXX", Email = "[email protected]", City = "XXXXX", DateCreated = DateTime.Now });
        _context.People.Add(new Person()
        { Id = 2, Firstname = "YYYYY", Lastname = "YYYYYYY", Email = "[email protected]", City = "YYYYY", DateCreated = DateTime.Now });
        _context.SaveChanges();

        _controller = new PeopleController(_context, _mapper);
    }

    [Test]
    public void GetAll_WhenCalled_ReturnPeopleInDb()
    {
        var result = _controller.GetPeople();

        var okObjectResult = result as OkObjectResult;
        var content = okObjectResult.Value as IEnumerable<Person>;
        Assert.IsNotNull(content);

    }

    private IMapper GenerateConcreteInstance()
    {
        var config = new AutoMapper.MapperConfiguration(c =>
        {
            c.AddProfile(new ApplicationProfile());
        });

        return config.CreateMapper();
    }
}

Would really appreciate any help, as I am new to ASP.NET Core and testing in general!

For integration testing (which is what you're doing here), you should use the test server. See: docs.microsoft.com/en-us/aspnet/core/test/… — Chris Pratt
Also more directly you do not save the data added to the context in setup. — Nkosi
@Nkosi Thank you, I have fixed that in the code. Still does not work, but will read up on using test server as suggested above by Chris Pratt. — Daniel Johansson

Chris Dan Chris Dan · Accepted Answer · 2019-10-16T17:49:51

You will have to call:

_context.SaveChanges()

to commit the changes to the database when adding new entries with _context.Add(T).

Testing ASP.NET Core API controller with InMemory

1 Answers