Throw error when calling ios commands on Windows or Linux (#412)

* Throw error when calling ios commands on Windows or Linux

* Update src/Microsoft.DotNet.XHarness.CLI/Commands/XHarnessHelpCommand.cs

Co-authored-by: Přemek Vysoký <premek.vysoky@microsoft.com>

Co-authored-by: Přemek Vysoký <premek.vysoky@microsoft.com>

Author: Katya Sokolova

src/Microsoft.DotNet.XHarness.CLI/Commands/XHarnessHelpCommand.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 using Microsoft.DotNet.XHarness.CLI.Android;
 using Microsoft.DotNet.XHarness.CLI.Commands.iOS;
 using Microsoft.DotNet.XHarness.CLI.Commands.Wasm;
@@ -39,7 +40,15 @@ public override int Invoke(IEnumerable<string> arguments)
                     PrintCommandHelp(new AndroidCommandSet(), subCommand);
                     break;
                 case "ios":
-                    PrintCommandHelp(new iOSCommandSet(), subCommand);
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                    {
+                        PrintCommandHelp(new iOSCommandSet(), subCommand);
+                    }
+                    else
+                    {
+                        Console.WriteLine($"Command '{command}' could be run on OSX only.");
+                    }
+                    
                     break;
                 case "wasm":
                     PrintCommandHelp(new WasmCommandSet(), subCommand);

src/Microsoft.DotNet.XHarness.CLI/Program.cs

@@ -4,6 +4,7 @@
 
 using System;
 using System.Linq;
+using System.Runtime.InteropServices;
 using Microsoft.DotNet.XHarness.CLI.Android;
 using Microsoft.DotNet.XHarness.CLI.Commands;
 using Microsoft.DotNet.XHarness.CLI.Commands.iOS;
@@ -23,7 +24,6 @@ public static int Main(string[] args)
             var commands = new CommandSet("xharness")
             {
                 // Add per-platform CommandSets - If adding  a new supported set, that goes here.
-                new iOSCommandSet(),
                 new AndroidCommandSet(),
                 new WasmCommandSet(),
 
@@ -32,6 +32,12 @@ public static int Main(string[] args)
                 new XHarnessVersionCommand(),
             };
 
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                commands.Add(new iOSCommandSet());
+            }
+            
+
             // Mono.Options wouldn't allow "--" and CommandSet parser will temporarily rename it
             int result = commands.Run(args.Select(a => a == "--" ? XHarnessCommand.VerbatimArgumentPlaceholder : a));
             Console.WriteLine($"XHarness exit code: {result}");

src/Microsoft.DotNet.XHarness.CLI/Properties/launchSettings.json

@@ -1,8 +1,8 @@
 {
-    "profiles": {
-        "XHarness": {
-            "commandName": "Project",
-            "commandLineArgs": "ios state"
-        }
+  "profiles": {
+    "XHarness": {
+      "commandName": "Project",
+      "commandLineArgs": "help"
     }
-}
+  }
+}