public async Task Delete_ReturnsNotFoundIfNull()
{
_provider.Setup(x => x.GetValueAsync(It.IsAny <int>())).ReturnsAsync(null);
var result = await _controller.DeleteToDoList(1);
var contentResult = result as NotFoundResult;
Assert.IsNotNull(contentResult);
Assert.IsInstanceOfType(contentResult, typeof(NotFoundResult));
}