spectreconsole-examples/examples/Cli/Testing/CommandAppTests.cs

using Spectre.Console;
using Spectre.Console.Cli;
using Spectre.Console.Testing;

namespace Testing;

[TestClass]
public class CommandAppTests
{
    /// <summary>
    /// A Spectre.Console Command
    /// </summary>
    public class HelloWorldCommand : Command
    {
        private readonly IAnsiConsole _console;

        public HelloWorldCommand(IAnsiConsole console)
        {
            // nb. AnsiConsole should not be called directly by the command
            // since this doesn't play well with testing. Instead,
            // the command should inject a IAnsiConsole and use that.

            _console = console;
        }

        public override int Execute(CommandContext context)
        {
            _console.WriteLine("Hello world.");
            return 0;
        }
    }

    [TestMethod]
    public void Should_Output_Hello_World()
    {
        // Given
        var app = new CommandAppTester();
        app.SetDefaultCommand<HelloWorldCommand>();

        // When
        var result = app.Run();

        // Then
        Assert.AreEqual(result.ExitCode, 0);
        Assert.AreEqual(result.Output, "Hello world.");
    }
}