diff --git a/tests/Help.tests.ps1 b/tests/Help.tests.ps1
index a6f3f46..836f1c9 100644
--- a/tests/Help.tests.ps1
+++ b/tests/Help.tests.ps1
@@ -72,7 +72,7 @@ BeforeDiscovery {
         # the values it needs (BHPSModuleManifest, BHProjectName) — when running
         # via ./build.ps1 this happens before psake; running tests in isolation
         # bypasses that, so we do it here.
-        Set-BuildEnvironment -Path (Split-Path -Parent $PSScriptRoot) -Force
+        Set-BuildEnvironment -Path (Split-Path -Path $PSScriptRoot -Parent) -Force
         $buildFilePath = Join-Path -Path $PSScriptRoot -ChildPath '..\build.psake.ps1'
         $invokePsakeParameters = @{
             TaskList  = 'Build'
@@ -82,10 +82,10 @@ BeforeDiscovery {
     }
 
     # PowerShellBuild outputs to Output/<ModuleName>/<Version>/, override BHBuildOutput
-    $projectRoot = Split-Path -Parent $PSScriptRoot
-    $sourceManifest = Join-Path $projectRoot "$Env:BHProjectName/$Env:BHProjectName.psd1"
-    $moduleVersion = (Import-PowerShellDataFile -Path $sourceManifest).ModuleVersion
-    $Env:BHBuildOutput = Join-Path $projectRoot "Output/$Env:BHProjectName/$moduleVersion"
+    $projectRoot = Split-Path -Path $PSScriptRoot -Parent
+    $sourceManifest = Join-Path -Path $projectRoot -ChildPath "$Env:BHProjectName/$Env:BHProjectName.psd1"
+    $moduleVersion = (Import-PowerShellDataFile $sourceManifest).ModuleVersion
+    $Env:BHBuildOutput = Join-Path -Path $projectRoot -ChildPath "Output/$Env:BHProjectName/$moduleVersion"
 
     # Define the path to the module manifest
     $moduleManifestFilename = $Env:BHProjectName + '.psd1'
@@ -104,7 +104,7 @@ BeforeDiscovery {
 
     # Remove all versions of the module from the session. Pester can't handle multiple versions.
     Get-Module $Env:BHProjectName | Remove-Module -Force -ErrorAction 'Ignore'
-    Import-Module -Name $moduleManifestPath -Verbose:$false -ErrorAction 'Stop'
+    Import-Module $moduleManifestPath -Verbose:$false -ErrorAction 'Stop'
 
     # Get module commands
     $getCommandParameters = @{
@@ -130,7 +130,7 @@ BeforeAll {
         # the values it needs (BHPSModuleManifest, BHProjectName) — when running
         # via ./build.ps1 this happens before psake; running tests in isolation
         # bypasses that, so we do it here.
-        Set-BuildEnvironment -Path (Split-Path -Parent $PSScriptRoot) -Force
+        Set-BuildEnvironment -Path (Split-Path -Path $PSScriptRoot -Parent) -Force
         $buildFilePath = Join-Path -Path $PSScriptRoot -ChildPath '..\build.psake.ps1'
         $invokePsakeParameters = @{
             TaskList  = 'Build'
@@ -148,10 +148,10 @@ Describe "Test help for <_.Name>" -ForEach $commands {
         # -ForEach, which Pester evaluates during discovery (before BeforeAll runs).
         $command               = $_
         $commandName           = $command.Name
-        $commandHelp           = Get-Help -Name $command.Name -ErrorAction 'SilentlyContinue'
-        $commandParameters     = global:FilterOutCommonParameters -Parameters $command.ParameterSets.Parameters
+        $commandHelp           = Get-Help $command.Name -ErrorAction 'SilentlyContinue'
+        $commandParameters     = global:FilterOutCommonParameters $command.ParameterSets.Parameters
         $commandParameterNames = $commandParameters.Name
-        $helpParameters        = global:FilterOutCommonParameters -Parameters $commandHelp.Parameters.Parameter
+        $helpParameters        = global:FilterOutCommonParameters $commandHelp.Parameters.Parameter
         $helpParameterNames    = $helpParameters.Name
         $helpLinks             = $commandHelp.relatedLinks.navigationLink.uri | Where-Object { $_ -match '^https?://' }
     }
@@ -160,10 +160,10 @@ Describe "Test help for <_.Name>" -ForEach $commands {
         # These variables are needed in both discovery and test phases so we need to duplicate them here
         $command                = $_
         $commandName            = $_.Name
-        $commandHelp            = Get-Help -Name $command.Name -ErrorAction 'SilentlyContinue'
-        $commandParameters      = global:FilterOutCommonParameters -Parameters $command.ParameterSets.Parameters
+        $commandHelp            = Get-Help $command.Name -ErrorAction 'SilentlyContinue'
+        $commandParameters      = global:FilterOutCommonParameters $command.ParameterSets.Parameters
         $commandParameterNames  = $commandParameters.Name
-        $helpParameters         = global:FilterOutCommonParameters -Parameters $commandHelp.Parameters.Parameter
+        $helpParameters         = global:FilterOutCommonParameters $commandHelp.Parameters.Parameter
         $helpParameterNames     = $helpParameters.Name
     }
 
@@ -217,8 +217,20 @@ Describe "Test help for <_.Name>" -ForEach $commands {
 
         # Required value in Help should match IsMandatory property of parameter
         It 'Has correct [mandatory] value' {
-            $codeMandatory = $_.IsMandatory.toString()
-            $parameterHelp.Required | Should -Be $codeMandatory
+            # Skip parameters that have different mandatory status across parameter sets
+            $parameterSetsWithParam = $command.ParameterSets | Where-Object { $_.Parameters.Name -contains $parameterName }
+            $mandatoryValues = $parameterSetsWithParam | ForEach-Object {
+                ($_.Parameters | Where-Object { $_.Name -eq $parameterName }).IsMandatory
+            } | Sort-Object -Unique
+
+            if ($mandatoryValues.Count -gt 1) {
+                Set-ItResult -Skipped -Because "Parameter '$parameterName' has varying mandatory status across parameter sets"
+                return
+            }
+
+            $codeMandatory = $_.IsMandatory.toString().ToLower()
+            $helpRequired = $parameterHelp.Required.ToLower()
+            $helpRequired | Should -Be $codeMandatory
         }
 
         # Parameter type in help should match code
diff --git a/tests/Meta.tests.ps1 b/tests/Meta.tests.ps1
index 68298f0..c3addf4 100644
--- a/tests/Meta.tests.ps1
+++ b/tests/Meta.tests.ps1
@@ -2,7 +2,7 @@ BeforeAll {
     Set-StrictMode -Version 'Latest'
 
     # Make sure MetaFixers.psm1 is loaded - it contains Get-TextFilesList
-    Import-Module -Name (Join-Path -Path $PSScriptRoot -ChildPath 'MetaFixers.psm1') -Verbose:$false -Force
+    Import-Module (Join-Path -Path $PSScriptRoot -ChildPath 'MetaFixers.psm1') -Verbose:$false -Force
 
     $projectRoot = $Env:BHProjectPath
     if (-not $projectRoot) {
@@ -24,7 +24,7 @@ BeforeAll {
         $unicodeFilesCount | Should -Be 0
 
         $fileName = $textFile.FullName
-        (Get-Content $fileName -Raw) | Select-String "`t" | Foreach-Object {
+        (Get-Content -Path $fileName -Raw) | Select-String "`t" | Foreach-Object {
             Write-Warning (
                 "There are tabs in $fileName." +
                 ' Use Fixer "Get-TextFilesList `$pwd | ConvertTo-SpaceIndentation".'
diff --git a/tests/MetaFixers.psm1 b/tests/MetaFixers.psm1
index 7dec0c8..5c614df 100644
--- a/tests/MetaFixers.psm1
+++ b/tests/MetaFixers.psm1
@@ -27,6 +27,7 @@ function ConvertTo-UTF8 {
     [OutputType([void])]
     param(
         [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+        [ValidateNotNull()]
         [System.IO.FileInfo]$FileInfo
     )
 
@@ -56,6 +57,7 @@ function ConvertTo-SpaceIndentation {
     [OutputType([void])]
     param(
         [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+        [ValidateNotNull()]
         [System.IO.FileInfo]$FileInfo
     )
 
@@ -85,6 +87,7 @@ function Get-TextFilesList {
     [OutputType([System.IO.FileInfo])]
     param(
         [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+        [ValidateNotNullOrEmpty()]
         [string]$Root
     )
 
@@ -159,6 +162,7 @@ function Get-UnicodeFilesList {
     [OutputType([System.IO.FileInfo])]
     param(
         [Parameter(Mandatory = $true)]
+        [ValidateNotNullOrEmpty()]
         [string]$Root
     )