public void DeletePicture() { MockDAL mock = new MockDAL(); mock.InsertAllPictures(); mock.InsertAllEXIFData(); mock.InsertAllIPTCData(); int count_before = mock.PictureList.Count; mock.DeletePicture("IAmBatman"); Assert.That(mock.PictureList.Count, Is.LessThan(count_before)); }