fix: update help text generator to display HelpOption correctly (#323)

Author: daveMueller

src/CommandLineUtils/CommandLineApplication.cs

@@ -998,7 +998,7 @@ public virtual void ShowHint()
                 var flag = !string.IsNullOrEmpty(OptionHelp.LongName)
                     ? "--" + OptionHelp.LongName
                     : !string.IsNullOrEmpty(OptionHelp.ShortName)
-                        ? "-" + OptionHelp.LongName
+                        ? "-" + OptionHelp.ShortName
                         : "-" + OptionHelp.SymbolName;
 
                 Out.WriteLine($"Specify {flag} for a list of available options and commands.");

src/CommandLineUtils/HelpText/DefaultHelpTextGenerator.cs

@@ -278,7 +278,7 @@ protected virtual void GenerateCommands(
                 if (application.OptionHelp != null)
                 {
                     output.WriteLine();
-                    output.WriteLine($"Run '{application.Name} [command] --{application.OptionHelp.LongName}' for more information about a command.");
+                    output.WriteLine($"Run '{application.Name} [command] {Format(application.OptionHelp)}' for more information about a command.");
                 }
             }
         }

test/CommandLineUtils.Tests/CommandLineApplicationTests.cs

@@ -7,6 +7,7 @@
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
+using Moq;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -1052,5 +1053,21 @@ public async Task OperationCanceledReturnsExpectedOsCode()
             var exitCode = await executeTask;
             Assert.Equal(expectedCode, exitCode);
         }
+
+        [Theory]
+        [InlineData("-h")]
+        [InlineData("--h")]
+        [InlineData("-?")]
+        public void ShowHintDisplaysValidInfo(string helpOption)
+        {
+            var app = new CommandLineApplication();
+            var textWriter = new Mock<TextWriter>();
+            app.Out = textWriter.Object;
+            app.HelpOption(helpOption);
+
+            app.ShowHint();
+
+            textWriter.Verify(mock => mock.WriteLine($"Specify {helpOption} for a list of available options and commands."), Times.Once);
+        }
     }
 }

test/CommandLineUtils.Tests/DefaultHelpTextGeneratorTests.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using McMaster.Extensions.CommandLineUtils.HelpText;
@@ -175,5 +177,34 @@ public class MyApp
             [Argument(1, Description = "enum arg desc")]
             public SomeEnum SomeEnumArgument { get; set; }
         }
+
+        [Theory]
+        [InlineData("-h", "-h", "  -h          Show help information", "  Subcommand ")]
+        [InlineData("--help", "--help", "  --help      Show help information", "  Subcommand ")]
+        [InlineData("-?", "-?", "  -?          Show help information", "  Subcommand ")]
+        [InlineData(null, "-?|-h|--help", "  -?|-h|--help  Show help information", "  Subcommand   ")]
+        public void ShowHelpWithSubcommands(string helpOption, string expectedHintText, string expectedOptionsText,
+            string expectedCommandsText)
+        {
+            var app = new CommandLineApplication {Name = "test"};
+            if (helpOption != null) app.HelpOption(helpOption);
+            app.Command("Subcommand", _ => { });
+            app.Conventions.UseDefaultConventions();
+            var helpText = GetHelpText(app);
+
+            Assert.Equal($@"Usage: test [command] [options]
+
+Options:
+{expectedOptionsText}
+
+Commands:
+{expectedCommandsText} 
+
+Run 'test [command] {expectedHintText}' for more information about a command.
+
+",
+                helpText,
+                ignoreLineEndingDifferences: true);
+        }
     }
 }