public async Task GetAllByAuthorWithCancellationDoesNotAcceptNull()
        {
            //arrange
            var repoMock = GetRepositoryMock();
            var sut      = new PollAggregate(repoMock.Object);

            //act & assert
            await Assert.ThrowsAsync <ArgumentNullException>(() => sut.GetAllByAuthorAsync(null, new CancellationTokenSource().Token));
        }
        public async Task GetAllByAuthorWithCancellationInvokesRepo()
        {
            //arrange
            var repoMock = GetRepositoryMock();
            var sut      = new PollAggregate(repoMock.Object);

            //act
            await sut.GetAllByAuthorAsync(new SchedUser(Guid.NewGuid(), ""), new CancellationTokenSource().Token);

            //assert
            repoMock.Verify(repo => repo.GetAllByAuthorAsync(It.IsAny <SchedUser>(), It.IsAny <CancellationToken>()), Times.Once);
        }