PowerShell · Pitchfork-and-Torch · Jul 11, 2026 · Jul 23, 2026
@@ -494,7 +494,7 @@ namespace PowershellTestConfigNamespace
 
                 It "Validate Register-PSSessionConfiguration with ApplicationBase, AssemblyName and ConfigurationTypeName parameter" -Pending {
 
-                    $null = Register-PSSessionConfiguration -Name $TestSessionConfigName -ApplicationBase $script:TestAssemblyDir -AssemblyName $LocalTestAssemblyName -ConfigurationTypeName "PowershellTestConfigNamespace.PowershellTestConfig" -force
+                    $null = Register-PSSessionConfiguration -Name $TestSessionConfigName -ApplicationBase $script:TestAssemblyDir -AssemblyName $LocalTestAssemblyName -ConfigurationTypeName "PowershellTestConfigNamespace.PowershellTestConfig" -Force
 
                     ValidateRemoteEndpoint -TestSessionConfigName $TestSessionConfigName -ScriptToExecute $null -ExpectedOutput $true -ExpectedError $null
                 }
@@ -566,7 +566,7 @@ namespace PowershellTestConfigNamespace
 
                 It "Validate Set-PSSessionConfiguration with ApplicationBase, AssemblyName and ConfigurationTypeName parameter" -Pending {
 
-                    $null = Set-PSSessionConfiguration -Name $TestSessionConfigName -ApplicationBase $script:TestAssemblyDir -AssemblyName $LocalTestAssemblyName -ConfigurationTypeName "PowershellTestConfigNamespace.PowershellTestConfig" -force
+                    $null = Set-PSSessionConfiguration -Name $TestSessionConfigName -ApplicationBase $script:TestAssemblyDir -AssemblyName $LocalTestAssemblyName -ConfigurationTypeName "PowershellTestConfigNamespace.PowershellTestConfig" -Force
 
                     ValidateRemoteEndpoint -TestSessionConfigName $TestSessionConfigName -ScriptToExecute $null -ExpectedOutput $true -ExpectedError $null
                 }

@@ -102,7 +102,7 @@ Describe "Basic FileSystem Provider Tests" -Tags "CI" {
             $topPath = Join-Path $TestDrive $longDir
             $longDirPath = Join-Path $topPath $longSubDir
             $longFilePath = Join-Path $longDirPath $fileName
-            $null = New-Item -itemtype file -path $longFilePath -force
+            $null = New-Item -ItemType file -Path $longFilePath -Force
 
             $longFilePath | Should -Exist
 

@@ -173,7 +173,7 @@ Describe "Remove-Item" -Tags "CI" {
             $streamfile = Join-Path -Path $testpath -ChildPath $fileName
             $streamdir = Join-Path -Path $testpath -ChildPath $dirName
 
-            $null = New-Item -Path $streamfile -ItemType "File" -force
+            $null = New-Item -Path $streamfile -ItemType "File" -Force
             Add-Content -Path $streamfile -Value $fileContent
             Add-Content -Path $streamfile -Stream $streamName -Value $streamContent
             $null = New-Item -Path $streamdir -ItemType "Directory" -Force

@@ -158,7 +158,7 @@ Describe "Get-Alias DRT Unit Tests" -Tags "CI" {
 
     It "Get-Alias DisplayName should always show AliasName -> ResolvedCommand for all aliases" {
         Set-Alias -Name Test-MyAlias -Value Get-Command -Force
-        Set-Alias -Name tma -Value Test-MyAlias -force
+        Set-Alias -Name tma -Value Test-MyAlias -Force
         $aliases = Get-Alias Test-MyAlias, tma
         $aliases | ForEach-Object {
             $_.DisplayName | Should -Be "$($_.Name) -> Get-Command"

@@ -118,7 +118,7 @@ Describe "File encoding tests" -Tag CI {
             )
         }
         BeforeEach {
-            Remove-Item TESTDRIVE:/* -force -ErrorAction Ignore
+            Remove-Item TESTDRIVE:/* -Force -ErrorAction Ignore
         }
         It "'<command> has a warning when '-Encoding utf7' is used" -TestCases $testCases {
             param ($command, $script)

@@ -0,0 +1,56 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+# Guardrail for parameter casing in PowerShell tests (see #26614).
+# Parameters are case-insensitive at runtime, but source style prefers PascalCase
+# (e.g. -Force, -ErrorAction) for readability and consistency with docs/examples.
+
+Describe "Parameter capitalization in PowerShell test scripts" -Tags @("CI") {
+    BeforeAll {
+        # test/powershell/engine/Basic -> repo root is four levels up
+        $repoRoot = (Resolve-Path (Join-Path $PSScriptRoot "../../../..")).Path
+        $scanRoot = Join-Path $repoRoot "test/powershell"
+
+        # High-frequency switches that should appear PascalCase in source.
+        # Intentional lowercase uses (binding case-insensitivity tests, stream fixtures)
+        # are allowlisted by relative path below.
+        # Negative lookbehind allows start-of-line as well as whitespace/pipe.
+        $parameterPattern = '(?<![\w-])-(force|erroraction|warningaction|verbose|debug|whatif|confirm)(?=[\s:\|]|$)'
+
+        $allowlistRelativePaths = @(
+            "test/powershell/Language/Scripting/CommonParameters.Tests.ps1"
+            "test/powershell/Language/Parser/BNotOperator.Tests.ps1"
+            "test/powershell/Language/Parser/RedirectionOperator.Tests.ps1"
+        )
+    }
+
+    It "Flags fully-lowercase common parameters (e.g. -force / -erroraction)" {
+        $files = Get-ChildItem -Path $scanRoot -Recurse -Include *.ps1, *.psm1 -File -ErrorAction Stop
+
+        $violations = [System.Collections.Generic.List[string]]::new()
+        foreach ($file in $files) {
+            $rel = $file.FullName.Substring($repoRoot.Length).TrimStart('\', '/').Replace('\', '/')
+            if ($allowlistRelativePaths -contains $rel) {
+                continue
+            }
+
+            # Avoid automatic $matches variable
+            $stringHits = Select-String -Path $file.FullName -Pattern $parameterPattern -CaseSensitive -AllMatches
+            foreach ($hit in $stringHits) {
+                $trim = $hit.Line.TrimStart()
+                # Comments that only discuss the switch are fine.
+                if ($trim.StartsWith('#')) {
+                    continue
+                }
+                $violations.Add(("{0}:{1}: {2}" -f $rel, $hit.LineNumber, $hit.Line.Trim()))
+            }
+        }
+
+        if ($violations.Count -gt 0) {
+            $header = "Found $($violations.Count) lowercase common-parameter(s). Prefer PascalCase (e.g. -Force, -ErrorAction). See PowerShell/PowerShell#26614."
+            throw ($header + [Environment]::NewLine + ($violations -join [Environment]::NewLine))
+        }
+
+        $violations.Count | Should -Be 0
+    }
+}