From 14241c5be09d6eaa14a28bf2d7615065028e35f6 Mon Sep 17 00:00:00 2001
From: Copilot <198982749+Copilot@users.noreply.github.com>
Date: Fri, 12 Dec 2025 09:26:46 +0500
Subject: [PATCH] Fix $PSDefaultParameterValues leak causing tests to skip
 unexpectedly (#26602)

This fixes test isolation issues where six test files were leaking $PSDefaultParameterValues["It:Skip"] settings to subsequent tests, causing widespread test skipping on Linux. The fixes address two distinct patterns: using .Remove() which doesn't restore the original state (4 files), and imbalanced Push-DefaultParameterValueStack/Pop-DefaultParameterValueStack calls (2 files).
---
 .../Microsoft.PowerShell.Management/Rename-Computer.Tests.ps1 | 3 ++-
 .../Microsoft.PowerShell.Security/AclCmdlets.Tests.ps1        | 3 ++-
 test/powershell/engine/ETS/CimAdapter.Tests.ps1               | 4 +++-
 test/powershell/engine/Remoting/RemoteSession.Basic.Tests.ps1 | 2 --
 test/powershell/engine/Remoting/SessionOption.Tests.ps1       | 3 ++-
 test/powershell/engine/Security/FileSignature.Tests.ps1       | 1 +
 6 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Computer.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Computer.Tests.ps1
index 82f944612f9..f1937f824a6 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Computer.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Computer.Tests.ps1
@@ -7,6 +7,7 @@ $DefaultResultValue = 0
 try
 {
     # set up for testing
+    $originalDefaultParameterValues = $PSDefaultParameterValues.Clone()
     $PSDefaultParameterValues["it:skip"] = ! $IsWindows
     Enable-Testhook -testhookName $RenameTesthook
     # we also set TestStopComputer
@@ -73,7 +74,7 @@ try
 }
 finally
 {
-    $PSDefaultParameterValues.Remove("it:skip")
+    $global:PSDefaultParameterValues = $originalDefaultParameterValues
     Disable-Testhook -testhookName $RenameTestHook
     Disable-Testhook -testhookName TestStopComputer
     Set-TesthookResult -testhookName $RenameResultName -value 0
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Security/AclCmdlets.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Security/AclCmdlets.Tests.ps1
index 0e50d7c3603..52938a0b881 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Security/AclCmdlets.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Security/AclCmdlets.Tests.ps1
@@ -3,6 +3,7 @@
 Describe "Acl cmdlets are available and operate properly" -Tag CI {
     Context "Windows ACL test" {
         BeforeAll {
+            $originalDefaultParameterValues = $PSDefaultParameterValues.Clone()
             $PSDefaultParameterValues["It:Skip"] = -not $IsWindows
         }
 
@@ -103,7 +104,7 @@ Describe "Acl cmdlets are available and operate properly" -Tag CI {
         }
 
         AfterAll {
-            $PSDefaultParameterValues.Remove("It:Skip")
+            $global:PSDefaultParameterValues = $originalDefaultParameterValues
         }
     }
 }
diff --git a/test/powershell/engine/ETS/CimAdapter.Tests.ps1 b/test/powershell/engine/ETS/CimAdapter.Tests.ps1
index 1e71bc28b95..3cfff4bd9e4 100644
--- a/test/powershell/engine/ETS/CimAdapter.Tests.ps1
+++ b/test/powershell/engine/ETS/CimAdapter.Tests.ps1
@@ -3,6 +3,8 @@
 
 Describe "CIM Objects are adapted properly" -Tag @("CI") {
     BeforeAll {
+        $originalDefaultParameterValues = $PSDefaultParameterValues.Clone()
+        
         function getIndex
         {
             param([string[]]$strings,[string]$pattern)
@@ -32,7 +34,7 @@ Describe "CIM Objects are adapted properly" -Tag @("CI") {
         }
     }
     AfterAll {
-        $PSDefaultParameterValues.Remove("it:pending")
+        $global:PSDefaultParameterValues = $originalDefaultParameterValues
     }
 
     It "Namespace-qualified Win32_Process is present" -Skip:(!$IsWindows) {
diff --git a/test/powershell/engine/Remoting/RemoteSession.Basic.Tests.ps1 b/test/powershell/engine/Remoting/RemoteSession.Basic.Tests.ps1
index a5d49b75005..2093eaa7ce5 100644
--- a/test/powershell/engine/Remoting/RemoteSession.Basic.Tests.ps1
+++ b/test/powershell/engine/Remoting/RemoteSession.Basic.Tests.ps1
@@ -83,9 +83,7 @@ Describe "JEA session Transcript script test" -Tag @("Feature", 'RequireAdminOnW
     AfterAll {
         if ($skipTest) {
             Pop-DefaultParameterValueStack
-            return
         }
-        Pop-DefaultParameterValueStack
     }
 
     It "Configuration name should be in the transcript header" {
diff --git a/test/powershell/engine/Remoting/SessionOption.Tests.ps1 b/test/powershell/engine/Remoting/SessionOption.Tests.ps1
index 1ff51e2a707..e85777e90ba 100644
--- a/test/powershell/engine/Remoting/SessionOption.Tests.ps1
+++ b/test/powershell/engine/Remoting/SessionOption.Tests.ps1
@@ -1,6 +1,7 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 try {
+    $originalDefaultParameterValues = $PSDefaultParameterValues.Clone()
     if ( ! $IsWindows ) {
         $PSDefaultParameterValues['it:skip'] = $true
     }
@@ -52,5 +53,5 @@ try {
     }
 }
 finally {
-    $PSDefaultParameterValues.remove("it:skip")
+    $global:PSDefaultParameterValues = $originalDefaultParameterValues
 }
diff --git a/test/powershell/engine/Security/FileSignature.Tests.ps1 b/test/powershell/engine/Security/FileSignature.Tests.ps1
index 51194903a94..9dd26f98aed 100644
--- a/test/powershell/engine/Security/FileSignature.Tests.ps1
+++ b/test/powershell/engine/Security/FileSignature.Tests.ps1
@@ -89,6 +89,7 @@ Describe "Windows file content signatures" -Tags @('Feature', 'RequireAdminOnWin
 
     AfterAll {
         if ($shouldSkip) {
+            Pop-DefaultParameterValueStack
             return
         }