public async void CanGetSizeOfPage() { var uri = new Uri("http://demo.com"); var mock = new Mock <IClient>(); var sizeCommand = new SizeCommand(uri, mock.Object); mock.Setup(c => c.GetAsync(uri, CancellationToken.None)).ReturnsAsync("12345"); var result = await sizeCommand.RunAsync(CancellationToken.None); Assert.Equal($"{uri} 5", result); }