IDbAsyncEnumerable not implemented

Question

I am trying to make a FakeDbContext with a FakeDbSet for unit testing.

But I get the following error (see below). I am extending DbSet so normally IDbAsyncEnumerable

Answer 1

Just a note for people using the boilerplate code discussed above from Microsoft, here is a quick helper class that can transform your mocked up data into the async result. Just add to the bottom of the MS code and call with something like

var fakeDateAsMockAsyncQueryResult = new MockAsyncData().MockAsyncQueryResult(fakeDataList.AsQueryable());

.......

internal class MockAsyncData where T : class
{ 
    public Mock> MockAsyncQueryResult(IQueryable data)
    {
        var mockSet = new Mock>();

        mockSet.As>()
            .Setup(m => m.GetAsyncEnumerator())
            .Returns(new TestDbAsyncEnumerator(data.GetEnumerator()));

        mockSet.As>()
            .Setup(m => m.Provider)
            .Returns(new TestDbAsyncQueryProvider(data.Provider));

        mockSet.As>().Setup(m => m.Expression).Returns(data.Expression);
        mockSet.As>().Setup(m => m.ElementType).Returns(data.ElementType);
        mockSet.As>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator());

        return mockSet;
    }
}

It's the same code as in the MS example but generic and reusable from many different unit tests.