Adding '$pshome/cultureName/default.help.txt' to PowerShell Windows Core project. (#3032)

* Adding PowerShellHelpFiles package which contains default.help.txt to powershell-win-core

* Adding test case to validate that <pshome>/<culture>/default.help.txt is present. This is done by calling 'Get-Help'

* Updating get-help to skip searching for the help file when the InternalTestHooks.BypassOnlineHelpRetrieval is enable. This way, we force get-help to generate a metadata driven help object, which includes a helpUri that points to the fwlink defined in the cmdlet code.

* Updating get-help -online <cmdletName> tests to not delete the help files. Instead, I've added logic to get-help to not find the help file when the test hook BypassOnlineHelpRetrieval is enable.

src/System.Management.Automation/help/CommandHelpProvider.cs

@@ -210,15 +210,21 @@ namespace System.Management.Automation
             string moduleDir = null;
             string nestedModulePath = null;
 
+            // When InternalTestHooks.BypassOnlineHelpRetrieval is enable, we force get-help to generate a metadata
+            // driven object, which includes a helpUri that points to the fwlink defined in the cmdlet code.
+            // This means that we are not going to load the help content from the GetFromCommandCache and
+            // we are not going to read the help file.
+
             // Only gets help for Cmdlet or script command
             if (!isCmdlet && !isScriptCommand)
                 return null;
 
             // Check if the help of the command is already in the cache.
             // If not, try load the file specified by HelpFile property and retrieve help.
-            if (isCmdlet)
+            if (isCmdlet && !InternalTestHooks.BypassOnlineHelpRetrieval)
             {
                 result = GetFromCommandCache(cmdletInfo.ModuleName, cmdletInfo.Name, cmdletInfo.HelpCategory);
+
                 if (null == result)
                 {
                     // Try load the help file specified by CmdletInfo.HelpFile property
@@ -291,7 +297,7 @@ namespace System.Management.Automation
                         }
                     }
 
-                    if (!String.IsNullOrEmpty(helpFile))
+                    if (!String.IsNullOrEmpty(helpFile) && !InternalTestHooks.BypassOnlineHelpRetrieval)
                     {
                         if (!_helpFiles.Contains(helpFile))
                         {
@@ -306,7 +312,7 @@ namespace System.Management.Automation
             // in the appropriate UI culture subfolder of ModuleBase, and retrieve help
             // If still not able to get help, try search for a file called <NestedModuleName>-Help.xml
             // under the ModuleBase and the NestedModule's directory, and retrieve help
-            if (null == result)
+            if (null == result && !InternalTestHooks.BypassOnlineHelpRetrieval)
             {
                 // Get the name and ModuleBase directory of the command's module
                 // and the nested module that implements the command
@@ -542,6 +548,13 @@ namespace System.Management.Automation
         /// <returns></returns>
         private string FindHelpFile(CmdletInfo cmdletInfo)
         {
+            if (InternalTestHooks.BypassOnlineHelpRetrieval)
+            {
+                // By returning null, we force get-help to generate a metadata driven help object,
+                // which includes a helpUri that points to the fwlink defined in the cmdlet code.
+                return null;
+            }
+
             if (cmdletInfo == null)
             {
                 throw PSTraceSource.NewArgumentNullException("cmdletInfo");

src/System.Management.Automation/help/ProviderContext.cs

@@ -4,6 +4,7 @@ Copyright (c) Microsoft Corporation.  All rights reserved.
 
 using System.Management.Automation.Provider;
 using System.Xml;
+using System.Management.Automation.Internal;
 
 using Dbg = System.Management.Automation.Diagnostics;
 
@@ -51,6 +52,13 @@ namespace System.Management.Automation
         /// </summary>
         internal MamlCommandHelpInfo GetProviderSpecificHelpInfo(string helpItemName)
         {
+            if (InternalTestHooks.BypassOnlineHelpRetrieval)
+            {
+                // By returning null, we force get-help to return generic help
+                // which includes a helpUri that points to the fwlink defined in the cmdlet code.
+                return null;
+            }
+
             // Get the provider.
             ProviderInfo providerInfo = null;
             PSDriveInfo driveInfo = null;

src/powershell-win-core/project.json

@@ -85,7 +85,8 @@
         "Microsoft.PowerShell.LocalAccounts": "6.0.0-*",
         "Microsoft.Management.Infrastructure.CimCmdlets": "6.0.0-*",
         "Microsoft.WSMan.Management": "6.0.0-*",
-        "PSDesiredStateConfiguration": "1.0.0-alpha01"
+        "PSDesiredStateConfiguration": "1.0.0-alpha01",
+        "PowerShellHelpFiles": "1.0.0-alpha01"
     },
 
     "frameworks": {

test/powershell/engine/Help/HelpSystem.OnlineHelp.Tests.ps1

@@ -3,23 +3,16 @@
     # The csv files (V2Cmdlets.csv and V3Cmdlets.csv) contain a list of cmdlets and expected HelpURIs.
     # The HelpURI is part of the cmdlet metadata, and when the user runs 'get-help <cmdletName> -online'
     # the browser navigates to the address in the HelpURI. However, if a help file is present, the HelpURI
-    # on the file take precedence over the one in the cmdlet metadata. Therefore, the help content
-    # in the box needs to be deleted before running the tests, because otherwise, the HelpURI
-    # (when calling get-help -online) might not matched the one in the csv file.
+    # on the file take precedence over the one in the cmdlet metadata.
 
     BeforeAll {
         $SavedProgressPreference = $ProgressPreference
         $ProgressPreference = "SilentlyContinue"
 
-        # Enable the test hook
+        # Enable the test hook. This does the following:
+        # 1) get-help will not find a help file; instead, it will generate a metadata driven object.
+        # 2) get-help -online <cmdletName>  will return the helpuri instead of opening the default web browser.
         [system.management.automation.internal.internaltesthooks]::SetTestHook('BypassOnlineHelpRetrieval', $true)
-
-        # Remove the help content
-        Write-Verbose "Deleting help content for get-help -online tests" -Verbose
-        foreach ($path in @("$pshome\en-US", "$pshome\Modules"))
-        {
-            Get-ChildItem $path -Include "*help.xml" -Recurse -ea SilentlyContinue | Remove-Item -Force -ErrorAction SilentlyContinue
-        }
     }
 
     AfterAll {

test/powershell/engine/Help/HelpSystem.Tests.ps1

@@ -62,6 +62,17 @@ function RunTestCase
     }
 }
 
+Describe "Validate that <pshome>/<culture>/default.help.txt is present" -Tags @('CI') {
+
+    It "Get-Help returns information about the help system." {
+
+        $help = Get-Help
+        $help.Name | Should Be "default"
+        $help.Category | Should Be "HelpFile"
+        $help.Synopsis | Should Match "SHORT DESCRIPTION"
+    }
+}
+
 Describe "Validate that get-help <cmdletName> works" -Tags @('CI', 'RequireAdminOnWindows') {
     BeforeAll {
         $SavedProgressPreference = $ProgressPreference