Mocking EF core dbcontext and dbset

Question

I am using ASP.NET Core 2.2, EF Core and MOQ. When I run the test I am getting this error:

Message: System.NotSupportedException : Invalid setup on a

Answer 1

This is a development of R.Titovs answer done in ASP.NET Core 3.1:

Constructing the Moq (generic method)

The data is cloned to allow for tests to run in parallel and prevent a test to access data changed by another.

public static Mock> SetDbSetData(this Mock dbMock,
        IList list, bool clone = true) 
    where TEnt : class
{
    var clonedList = clone ? list.DeepClone().ToList() : list.ToList();
    var mockDbSet = clonedList.AsQueryable().BuildMockDbSet();

    dbMock.Setup(m => m.Set()).Returns(mockDbSet.Object);
    dbMock.Setup(m => m.ReadSet()).Returns(mockDbSet.Object.AsQueryable());

    return mockDbSet;
}

Using some test data

_appUserDbSetMock = _dbMock.SetDbSetData(ApplicationUserTestData.ApplicationUserData);

Example test

[Fact]
private async Task Handle_ShouldAddANewUser()
{
    var command = new CreateApplicationUserCommand
    {
        // ...
    };

    await _handler.Handle(command, default);

    _appUserDbSetMock.Verify(m => m.AddAsync(It.IsAny(), default), Times.Once);
}

One advantage of using MoqQueryable is that there is no need for a generic repository since DbSet acts like one and the mocking is very easy.