public void ArchiveById_Should_Archive_The_Correct_Amount() { // Arrange List <int> errors = new List <int> { 1, 2, 3, 20 }; var context = GenerateContext("ArchiveError"); var service = new ErrorService(context); // Act var result = service.ArchiveById(errors); // Assert Assert.NotNull(result); Assert.All(context.Errors.Where(x => errors.Contains(x.Id)), x => Assert.True(x.IsArchived)); Assert.True(result.Count == 1); // should return one error }