Help writer unit tests; including coverage of when the -v|--version should (and shouldn't) appear in the help output

src/Tests/Spectre.Console.Cli.Tests/Data/Settings/VersionSettings.cs

@@ -3,5 +3,6 @@ namespace Spectre.Console.Tests.Data;
 public sealed class VersionSettings : CommandSettings
 {
     [CommandOption("-v|--version")]
+    [Description("The command version")]
     public string Version { get; set; }
 }

src/Tests/Spectre.Console.Cli.Tests/Unit/CommandAppTests.Version.Help.cs

@@ -0,0 +1,242 @@
+namespace Spectre.Console.Tests.Unit.Cli;
+
+public sealed partial class CommandAppTests
+{
+    public sealed partial class Version
+    {
+        public sealed class Help
+        {
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Application_Version_Flag_With_No_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                });
+
+                // When
+                var result = fixture.Run(helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Not_Include_Application_Version_Flag_If_Not_Specified(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.AddCommand<EmptyCommand>("empty");
+                });
+
+                // When
+                var result = fixture.Run(helpOption);
+
+                // Then
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Not_Include_Application_Version_Flag_For_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddCommand<EmptyCommand>("empty");
+                });
+
+                // When
+                var result = fixture.Run("empty", helpOption);
+
+                // Then
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Application_Version_Flag_For_Default_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.SetDefaultCommand<EmptyCommand>();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                });
+
+                // When
+                var result = fixture.Run(helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Not_Include_Application_Version_Flag_For_Branch_Default_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddBranch<EmptyCommandSettings>("branch", branch =>
+                    {
+                        branch.SetDefaultCommand<EmptyCommand>();
+                    });
+                });
+
+                // When
+                var result = fixture.Run("branch", helpOption);
+
+                // Then
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Not_Include_Application_Version_Flag_For_Branch_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddBranch<EmptyCommandSettings>("branch", branch =>
+                    {
+                        branch.AddCommand<EmptyCommand>("hello");
+                    });
+                });
+
+                // When
+                var result = fixture.Run("branch", "hello", helpOption);
+
+                // Then
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Command_Version_Flag_For_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddCommand<Spectre.Console.Tests.Data.VersionCommand>("empty");
+                });
+
+                // When
+                var result = fixture.Run("empty", helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    The command version");
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            /// <summary>
+            /// When a command with a version flag in the settings is set as the application default command,
+            /// then override the in-built Application Version flag with the command version flag instead.
+            /// Rationale: This behaviour makes the most sense because the other flags for the default command
+            /// will be shown in the help output and the user can set any of these when executing the application.
+            /// </summary>
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Command_Version_Flag_For_Default_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.SetDefaultCommand<Spectre.Console.Tests.Data.VersionCommand>();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                });
+
+                // When
+                var result = fixture.Run(helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    The command version");
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Command_Version_Flag_For_Branch_Default_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddBranch<VersionSettings>("branch", branch =>
+                    {
+                        branch.SetDefaultCommand<Spectre.Console.Tests.Data.VersionCommand>();
+                    });
+                });
+
+                // When
+                var result = fixture.Run("branch", helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    The command version");
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+            [Theory]
+            [InlineData("-?")]
+            [InlineData("-h")]
+            [InlineData("--help")]
+            public void Help_Should_Include_Command_Version_Flag_For_Branch_Command(string helpOption)
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationVersion("1.0");
+                    configurator.AddBranch<VersionSettings>("branch", branch =>
+                    {
+                        branch.AddCommand<Spectre.Console.Tests.Data.VersionCommand>("hello");
+                    });
+                });
+
+                // When
+                var result = fixture.Run("branch", "hello", helpOption);
+
+                // Then
+                result.Output.ShouldContain("-v, --version    The command version");
+                result.Output.ShouldNotContain("-v, --version    Prints version information");
+            }
+
+
+        }
+    }
+}

src/Tests/Spectre.Console.Cli.Tests/Unit/CommandAppTests.Version.cs

@@ -2,7 +2,7 @@ namespace Spectre.Console.Tests.Unit.Cli;
 
 public sealed partial class CommandAppTests
 {
-    public sealed class Version
+    public sealed partial class Version
     {
         [Theory]
         [InlineData(false)]