Added the ability to hide CommandOptions. (#642)

CommandOptions now has an IsHidden property that, when set to true, will cause the option to be hidden from the following cases:

- Help text using `-h|--help`
- Xml representations generated with the `cli xml` command
- Diagnostics displayed with the `cli explain` command

Hidden options can still be outputted with `cli explain` using the `--hidden` option that is also used to display hidden commands.

Fixes #631

test/Spectre.Console.Tests/Data/Commands/HiddenOptionsCommand.cs

@@ -0,0 +1,12 @@
+using Spectre.Console.Cli;
+
+namespace Spectre.Console.Tests.Data
+{
+    public sealed class HiddenOptionsCommand : Command<HiddenOptionSettings>
+    {
+        public override int Execute(CommandContext context, HiddenOptionSettings settings)
+        {
+            return 0;
+        }
+    }
+}

test/Spectre.Console.Tests/Data/Settings/HiddenOptionSettings.cs

@@ -0,0 +1,20 @@
+using System.ComponentModel;
+using Spectre.Console.Cli;
+
+namespace Spectre.Console.Tests.Data
+{
+    public sealed class HiddenOptionSettings : CommandSettings
+    {
+        [CommandArgument(0, "<FOO>")]
+        [Description("Dummy argument FOO")]
+        public int Foo { get; set; }
+
+        [CommandOption("--bar", IsHidden = true)]
+        [Description("You should not be able to read this unless you used the 'cli explain' command with the '--hidden' option")]
+        public int Bar { get; set; }
+
+        [CommandOption("--baz")]
+        [Description("Dummy option BAZ")]
+        public int Baz { get; set; }
+    }
+}

test/Spectre.Console.Tests/Expectations/Cli/Help/Hidden_Command_Options.Output.verified.txt

@@ -0,0 +1,9 @@
+USAGE:
+    myapp <FOO> [OPTIONS]
+
+ARGUMENTS:
+    <FOO>    Dummy argument FOO
+
+OPTIONS:
+    -h, --help    Prints help information
+        --baz     Dummy option BAZ

test/Spectre.Console.Tests/Expectations/Cli/Xml/Hidden_Command_Options.Output.verified.txt

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Model>
+  <!--DEFAULT COMMAND-->
+  <Command Name="__default_command" IsBranch="false" IsDefault="true" ClrType="Spectre.Console.Tests.Data.HiddenOptionsCommand" Settings="Spectre.Console.Tests.Data.HiddenOptionSettings">
+    <Parameters>
+      <Argument Name="FOO" Position="0" Required="true" Kind="scalar" ClrType="System.Int32">
+        <Description>Dummy argument FOO</Description>
+      </Argument>
+      <Option Short="" Long="baz" Value="NULL" Required="false" Kind="scalar" ClrType="System.Int32">
+        <Description>Dummy option BAZ</Description>
+      </Option>
+    </Parameters>
+  </Command>
+</Model>

test/Spectre.Console.Tests/Unit/Cli/Annotations/CommandOptionAttributeTests.cs

@@ -193,5 +193,25 @@ namespace Spectre.Console.Tests.Unit.Cli.Annotations
             result.ShortNames.ShouldContain("f");
             result.ValueName.ShouldBe("BAR");
         }
+
+        [Fact]
+        public void Is_Not_Hidden_From_Help_By_Default()
+        {
+            // Given, When
+            var result = new CommandOptionAttribute("--foo");
+
+            // Then
+            result.IsHidden.ShouldBeFalse();
+        }
+
+        [Fact]
+        public void Can_Indicate_That_It_Must_Be_Hidden_From_Help_Text()
+        {
+            // Given, When
+            var result = new CommandOptionAttribute("--foo") { IsHidden = true };
+
+            // Then
+            result.IsHidden.ShouldBeTrue();
+        }
     }
 }

test/Spectre.Console.Tests/Unit/Cli/CommandAppTests.Help.cs

@@ -278,6 +278,25 @@ namespace Spectre.Console.Tests.Unit.Cli
                 // Then
                 return Verifier.Verify(result.Output);
             }
+
+            [Fact]
+            [Expectation("Hidden_Command_Options")]
+            public Task Should_Not_Show_Hidden_Command_Options()
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.SetDefaultCommand<GenericCommand<HiddenOptionSettings>>();
+                fixture.Configure(configurator =>
+                {
+                    configurator.SetApplicationName("myapp");
+                });
+
+                // When
+                var result = fixture.Run("--help");
+
+                // Then
+                return Verifier.Verify(result.Output);
+            }
         }
     }
 }

test/Spectre.Console.Tests/Unit/Cli/CommandAppTests.Xml.cs

@@ -137,6 +137,21 @@ namespace Spectre.Console.Tests.Unit.Cli
                 // Then
                 return Verifier.Verify(result.Output);
             }
+
+            [Fact]
+            [Expectation("Hidden_Command_Options")]
+            public Task Should_Not_Dump_Hidden_Options_On_A_Command()
+            {
+                // Given
+                var fixture = new CommandAppTester();
+                fixture.SetDefaultCommand<HiddenOptionsCommand>();
+
+                // When
+                var result = fixture.Run(Constants.XmlDocCommand);
+
+                // Then
+                return Verifier.Verify(result.Output);
+            }
         }
     }
 }