public async Task GetLikedSongIdsByUserIdAsync_UserIdNoLikedArtists_EmptyArray() { // Arrange var artistRepoMock = new Mock <IArtistRepository>(); artistRepoMock.Setup(mock => mock.GetLikedArtistIdsByUserIdAsync(1)) .ReturnsAsync(new int[] { }) .Verifiable(); var artistCollection = new ArtistCollection(artistRepoMock.Object, _dependencyMapper); // Act var likedArtists = (await artistCollection.GetLikedArtistIdsByUserIdAsync(1)).ToArray(); // Assert artistRepoMock.Verify(); Assert.AreEqual(0, likedArtists.Length); }