Import-SqlDscPreferredModule: Allow unit tests to run cross-plattfo…

…rm (#1852)

- `Import-SqlDscPreferredModule`
  - No longer tries to get the environment variables from the machine state
    when run on Linux or macOS. This will allow the unit tests to run
    cross-plattform.

CHANGELOG.md

@@ -149,6 +149,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Uninstall-SqlDscServer`
   - Was changed to support the SQL Server 2022 GA feature `AzureExtension`
     (that replaced the feature name `ARC`) ([issue #1798](https://github.com/dsccommunity/SqlServerDsc/issues/1798)).
+- `Import-SqlDscPreferredModule`
+  - No longer tries to get the environment variables from the machine state
+    when run on Linux or macOS. This will allow the unit tests to run
+    cross-plattform.
 - SqlReplication
   - The resource now supports SQL Server 2022. The resource will require
     the module _SqlServer_ v22.0.49-preview or newer when used against an

source/Public/Import-SqlDscPreferredModule.ps1

@@ -91,13 +91,17 @@ function Import-SqlDscPreferredModule
     {
         Write-Verbose -Message ($script:localizedData.PreferredModule_ModuleNotFound)
 
-        <#
-            After installing SQL Server the current PowerShell session doesn't know
-            about the new path that was added for the SQLPS module. This reloads
-            PowerShell session environment variable PSModulePath to make sure it
-            contains all paths.
-        #>
-        Set-PSModulePath -Path ([System.Environment]::GetEnvironmentVariable('PSModulePath', 'Machine'))
+        # Only run on Windows that has Machine state.
+        if (-not ($IsLinux -or $IsMacOS))
+        {
+            <#
+                After installing SQL Server the current PowerShell session doesn't know
+                about the new path that was added for the SQLPS module. This reloads
+                PowerShell session environment variable PSModulePath to make sure it
+                contains all paths.
+            #>
+            Set-PSModulePath -Path ([System.Environment]::GetEnvironmentVariable('PSModulePath', 'Machine'))
+        }
 
         # Get the newest SQLPS module if more than one exist.
         $availableModule = Get-Module -FullyQualifiedName 'SQLPS' -ListAvailable |