CliFx/CliFx.Tests/HelpTextSpecs.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using CliFx.Tests.Utils;
using CliFx.Tests.Utils.Extensions;
using FluentAssertions;
using Xunit;
using Xunit.Abstractions;

namespace CliFx.Tests;

public class HelpTextSpecs : SpecsBase
{
    public HelpTextSpecs(ITestOutputHelper testOutput)
        : base(testOutput)
    {
    }

    [Fact]
    public async Task I_can_request_the_help_text_by_running_the_application_without_arguments_if_the_default_command_is_not_defined()
    {
        // Arrange
        var application = new CliApplicationBuilder()
            .UseConsole(FakeConsole)
            .SetDescription("This will be in help text")
            .Build();

        // Act
        var exitCode = await application.RunAsync(
            Array.Empty<string>(),
            new Dictionary<string, string>()
        );

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("This will be in help text");
    }

    [Fact]
    public async Task I_can_request_the_help_text_by_running_the_application_with_the_help_option()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command]
            public class DefaultCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .SetDescription("This will be in help text")
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("This will be in help text");
    }

    [Fact]
    public async Task I_can_request_the_help_text_by_running_the_application_with_the_help_option_even_if_the_default_command_is_not_defined()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command("cmd")]
            public class NamedCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd child")]
            public class NamedChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .SetDescription("This will be in help text")
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("This will be in help text");
    }

    [Fact]
    public async Task I_can_request_the_help_text_for_a_specific_command_by_running_the_application_and_specifying_its_name_with_the_help_option()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command]
            public class DefaultCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd", Description = "Description of a named command.")]
            public class NamedCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd child")]
            public class NamedChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .Build();

        // Act
        var exitCode = await application.RunAsync(
            new[] {"cmd", "--help"},
            new Dictionary<string, string>()
        );

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("Description of a named command.");
    }

    [Fact]
    public async Task I_can_request_the_help_text_for_a_specific_nested_command_by_running_the_application_and_specifying_its_name_with_the_help_option()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command]
            public class DefaultCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd")]
            public class NamedCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd child", Description = "Description of a named child command.")]
            public class NamedChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .Build();

        // Act
        var exitCode = await application.RunAsync(
            new[] {"cmd", "sub", "--help"},
            new Dictionary<string, string>()
        );

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("Description of a named child command.");
    }

    [Fact]
    public async Task I_can_request_the_help_text_by_running_the_application_with_invalid_arguments()
    {
        // Arrange
        var application = new CliApplicationBuilder()
            .AddCommand<NoOpCommand>()
            .UseConsole(FakeConsole)
            .SetDescription("This will be in help text")
            .Build();

        // Act
        var exitCode = await application.RunAsync(
            new[] {"invalid-command", "--invalid-option"},
            new Dictionary<string, string>()
        );

        // Assert
        exitCode.Should().NotBe(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().Contain("This will be in help text");

        var stdErr = FakeConsole.ReadErrorString();
        stdErr.Should().NotBeNullOrWhiteSpace();
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_application_title_description_and_version()
    {
        // Arrange
        var application = new CliApplicationBuilder()
            .UseConsole(FakeConsole)
            .SetTitle("App title")
            .SetDescription("App description")
            .SetVersion("App version")
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAll(
            "App title",
            "App description",
            "App version"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_command_description()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command(Description = "Description of the default command.")]
            public class DefaultCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "DESCRIPTION",
            "Description of the default command."
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_usage_format_for_a_named_command()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command]
            public class DefaultCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd")]
            public class NamedCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "USAGE",
            "[command]", "[...]"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_usage_format_for_all_parameters()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command]
            public class Command : ICommand
            {
                [CommandParameter(0)]
                public required string Foo { get; init; }

                [CommandParameter(1)]
                public required string Bar { get; init; }

                [CommandParameter(2)]
                public required IReadOnlyList<string> Baz { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "USAGE",
            "<foo>", "<bar>", "<baz...>"
        );
    }

    // https://github.com/Tyrrrz/CliFx/issues/117
    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_usage_format_for_all_parameters_in_the_correct_order()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            // Base members appear last in reflection order
            public abstract class CommandBase : ICommand
            {
                [CommandParameter(0)]
                public required string Foo { get; init; }

                public abstract ValueTask ExecuteAsync(IConsole console);
            }

            [Command]
            public class Command : CommandBase
            {
                [CommandParameter(2)]
                public required IReadOnlyList<string> Baz { get; init; }

                [CommandParameter(1)]
                public required string Bar { get; init; }

                public override ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "USAGE",
            "<foo>", "<bar>", "<baz...>"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_usage_format_for_all_required_options()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command]
            public class Command : ICommand
            {
                [CommandOption("foo")]
                public required string Foo { get; init; }

                [CommandOption("bar")]
                public string? Bar { get; init; }

                [CommandOption("baz")]
                public required IReadOnlyList<string> Baz { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "USAGE",
            "--foo <value>", "--baz <values...>", "[options]"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_all_parameters_and_options()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command]
            public class Command : ICommand
            {
                [CommandParameter(0, Name = "foo", Description = "Description of foo.")]
                public string? Foo { get; init; }

                [CommandOption("bar", Description = "Description of bar.")]
                public string? Bar { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "PARAMETERS",
            "foo", "Description of foo.",
            "OPTIONS",
            "--bar", "Description of bar."
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_help_and_version_options()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command]
            public class Command : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "OPTIONS",
            "-h", "--help", "Shows help text",
            "--version", "Shows version information"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_on_a_named_command_to_see_the_help_option()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            [Command("cmd")]
            public class Command : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

        // Act
        var exitCode = await application.RunAsync(
            new[] {"cmd", "--help"},
            new Dictionary<string, string>()
        );

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();

        stdOut.Should().ContainAllInOrder(
            "OPTIONS",
            "-h", "--help", "Shows help text"
        );

        stdOut.Should().NotContainAny(
            "--version", "Shows version information"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_valid_values_for_all_parameters_and_options_bound_to_enum_properties()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            public enum CustomEnum { One, Two, Three }

            [Command]
            public class Command : ICommand
            {
                [CommandParameter(0)]
                public CustomEnum Foo { get; init; }

                [CommandOption("bar")]
                public CustomEnum Bar { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "PARAMETERS",
            "foo", "Choices:", "One", "Two", "Three",
            "OPTIONS",
            "--bar", "Choices:", "One", "Two", "Three"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_valid_values_for_all_parameters_and_options_bound_to_non_scalar_enum_properties()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            public enum CustomEnum { One, Two, Three }

            [Command]
            public class Command : ICommand
            {
                [CommandParameter(0)]
                public required IReadOnlyList<CustomEnum> Foo { get; init; }

                [CommandOption("bar")]
                public required IReadOnlyList<CustomEnum> Bar { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "PARAMETERS",
            "foo", "Choices:", "One", "Two", "Three",
            "OPTIONS",
            "--bar", "Choices:", "One", "Two", "Three"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_valid_values_for_all_parameters_and_options_bound_to_nullable_enum_properties()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            public enum CustomEnum { One, Two, Three }

            [Command]
            public class Command : ICommand
            {
                [CommandParameter(0)]
                public CustomEnum? Foo { get; init; }

                [CommandOption("bar")]
                public IReadOnlyList<CustomEnum?>? Bar { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "PARAMETERS",
            "foo", "Choices:", "One", "Two", "Three",
            "OPTIONS",
            "--bar", "Choices:", "One", "Two", "Three"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_environment_variables_of_options_that_use_them_as_fallback()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            public enum CustomEnum { One, Two, Three }

            [Command]
            public class Command : ICommand
            {
                [CommandOption("foo", EnvironmentVariable = "ENV_FOO")]
                public CustomEnum Foo { get; init; }

                [CommandOption("bar", EnvironmentVariable = "ENV_BAR")]
                public CustomEnum Bar { get; init; }

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "OPTIONS",
            "--foo", "Environment variable:", "ENV_FOO",
            "--bar", "Environment variable:", "ENV_BAR"
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_default_values_of_non_required_options()
    {
        // Arrange
        var commandType = DynamicCommandBuilder.Compile(
            // lang=csharp
            """
            public enum CustomEnum { One, Two, Three }

            [Command]
            public class Command : ICommand
            {
                [CommandOption("foo")]
                public object? Foo { get; init; } = 42;

                [CommandOption("bar")]
                public string? Bar { get; init; } = "hello";

                [CommandOption("baz")]
                public IReadOnlyList<string>? Baz { get; init; } = new[] {"one", "two", "three"};

                [CommandOption("qwe")]
                public bool Qwe { get; init; } = true;

                [CommandOption("qop")]
                public int? Qop { get; init; } = 1337;

                [CommandOption("zor")]
                public TimeSpan Zor { get; init; } = TimeSpan.FromMinutes(123);

                [CommandOption("lol")]
                public CustomEnum Lol { get; init; } = CustomEnum.Two;

                [CommandOption("hmm")]
                public required string Hmm { get; init; } = "not printed";

                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommand(commandType)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();

        stdOut.Should().ContainAllInOrder(
            "OPTIONS",
            "--foo", "Default:", "42",
            "--bar", "Default:", "hello",
            "--baz", "Default:", "one", "two", "three",
            "--qwe", "Default:", "True",
            "--qop", "Default:", "1337",
            "--zor", "Default:", "02:03:00",
            "--lol", "Default:", "Two"
        );

        stdOut.Should().NotContain("not printed");
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_all_immediate_child_commands()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command("cmd1", Description = "Description of one command.")]
            public class FirstCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd2", Description = "Description of another command.")]
            public class SecondCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd2 child", Description = "Description of another command's child command.")]
            public class SecondCommandChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd3 child", Description = "Description of an orphaned command.")]
            public class ThirdCommandChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();

        stdOut.Should().ContainAllInOrder(
            "COMMANDS",
            "cmd1", "Description of one command.",
            "cmd2", "Description of another command.",
            // `cmd2 child` will appear as an immediate command because it does not
            // have a more specific parent.
            "cmd3 child", "Description of an orphaned command."
        );

        // `cmd2 child` will still appear in the list of `cmd2` subcommands,
        // but its description will not be visible.
        stdOut.Should().NotContain(
            "Description of another command's child command."
        );
    }

    [Fact]
    public async Task I_can_request_the_help_text_to_see_the_list_of_all_immediate_grand_child_commands()
    {
        // Arrange
        var commandTypes = DynamicCommandBuilder.CompileMany(
            // lang=csharp
            """
            [Command("cmd1")]
            public class FirstCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd1 child1")]
            public class FirstCommandFirstChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd2")]
            public class SecondCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd2 child11")]
            public class SecondCommandFirstChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }

            [Command("cmd2 child2")]
            public class SecondCommandSecondChildCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """
        );

        var application = new CliApplicationBuilder()
            .AddCommands(commandTypes)
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Should().ContainAllInOrder(
            "COMMANDS",
            "cmd1", "Subcommands:", "cmd1 child1",
            "cmd2", "Subcommands:", "cmd2 child1", "cmd2 child2"
        );
    }

    [Fact]
    public async Task I_can_request_the_version_text_by_running_the_application_with_the_version_option()
    {
        // Arrange
        var application = new CliApplicationBuilder()
            .AddCommand<NoOpCommand>()
            .SetVersion("v6.9")
            .UseConsole(FakeConsole)
            .Build();

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

        // Assert
        exitCode.Should().Be(0);

        var stdOut = FakeConsole.ReadOutputString();
        stdOut.Trim().Should().Be("v6.9");
    }
}