CliFx/CliFx.Tests/CancellationSpecs.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using FluentAssertions;
using Xunit;

namespace CliFx.Tests
{
    public partial class CancellationSpecs
    {
        [Fact]
        public async Task Command_can_perform_additional_cleanup_if_cancellation_is_requested()
        {
            // Arrange
            using var cts = new CancellationTokenSource();

            await using var stdOut = new MemoryStream();
            var console = new VirtualConsole(output: stdOut, cancellationToken: cts.Token);

            var application = new CliApplicationBuilder()
                .AddCommand(typeof(CancellableCommand))
                .UseConsole(console)
                .Build();

            // Act
            cts.CancelAfter(TimeSpan.FromSeconds(0.2));

            var exitCode = await application.RunAsync(
                new[] {"cancel"},
                new Dictionary<string, string>());

            var stdOutData = console.Output.Encoding.GetString(stdOut.ToArray()).TrimEnd();

            // Assert
            exitCode.Should().NotBe(0);
            stdOutData.Should().Be("Cancellation requested");
        }
    }
}