Made code more resilient against mocking Get-Command

Functions/Assertions/Should.ps1

@@ -34,7 +34,7 @@ function Parse-ShouldArgs([array] $shouldArgs) {
 
 function Get-TestResult($shouldArgs, $value) {
     $assertionMethod = $shouldArgs.AssertionMethod
-    $command = Get-Command $assertionMethod -CommandType Function -ErrorAction $script:IgnoreErrorPreference
+    $command = & $SafeCommands['Get-Command'] $assertionMethod -CommandType Function -ErrorAction $script:IgnoreErrorPreference
 
     if ($null -eq $command)
     {

Functions/It.ps1

@@ -391,7 +391,7 @@ function Get-ParameterDictionary
     try
     {
         & $SafeCommands['Set-Content'] function:\$guid $ScriptBlock
-        $metadata = [System.Management.Automation.CommandMetadata](Get-Command -Name $guid -CommandType Function)
+        $metadata = [System.Management.Automation.CommandMetadata](& $SafeCommands['Get-Command'] -Name $guid -CommandType Function)
 
         return $metadata.Parameters
     }

Functions/Mock.ps1

@@ -330,7 +330,7 @@ about_Mocking
             $mock.Alias = "$($mock.OriginalCommand.ModuleName)\$($CommandName)"
 
             $scriptBlock = {
-                $setAlias = Get-Command -Name Set-Alias -CommandType Cmdlet -Module Microsoft.PowerShell.Utility
+                $setAlias = & (Pester\SafeGetCommand) -Name Set-Alias -CommandType Cmdlet -Module Microsoft.PowerShell.Utility
                 & $setAlias -Name $args[0] -Value $args[1] -Scope Script
             }
 
@@ -720,8 +720,8 @@ function Validate-Command([string]$CommandName, [string]$ModuleName) {
     $commandInfo = & $SafeCommands['New-Object'] psobject -Property @{ Command = $null; Scope = '' }
 
     $scriptBlock = {
-        $getContentCommand = Get-Command Get-Content -Module Microsoft.PowerShell.Management -CommandType Cmdlet
-        $newObjectCommand  = Get-Command New-Object  -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet
+        $getContentCommand = & (Pester\SafeGetCommand) Get-Content -Module Microsoft.PowerShell.Management -CommandType Cmdlet
+        $newObjectCommand  = & (Pester\SafeGetCommand) New-Object  -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet
 
         $command = $ExecutionContext.InvokeCommand.GetCommand($args[0], 'All')
         while ($null -ne $command -and $command.CommandType -eq [System.Management.Automation.CommandTypes]::Alias)
@@ -793,7 +793,7 @@ function MockPrototype {
         [string] ${ignore preference} = 'SilentlyContinue'
     }
 
-    ${get Variable Command} = Get-Command -Name Get-Variable -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
+    ${get Variable Command} = & (Pester\SafeGetCommand) -Name Get-Variable -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
 
     [object] ${a r g s} = & ${get Variable Command} -Name args -ValueOnly -Scope Local -ErrorAction ${ignore preference}
     if ($null -eq ${a r g s}) { ${a r g s} = @() }
@@ -1265,7 +1265,7 @@ function Get-DynamicParametersForCmdlet
 
     try
     {
-        $command = Get-Command -Name $CmdletName -CommandType Cmdlet -ErrorAction Stop
+        $command = & $SafeCommands['Get-Command'] -Name $CmdletName -CommandType Cmdlet -ErrorAction Stop
 
         if (@($command).Count -gt 1)
         {

Functions/PesterState.ps1

@@ -52,10 +52,10 @@ function New-PesterState
 
         $script:SafeCommands = @{}
 
-        $script:SafeCommands['New-Object']          = Get-Command -Name New-Object          -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
-        $script:SafeCommands['Select-Object']       = Get-Command -Name Select-Object       -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
-        $script:SafeCommands['Export-ModuleMember'] = Get-Command -Name Export-ModuleMember -Module Microsoft.PowerShell.Core    -CommandType Cmdlet
-        $script:SafeCommands['Add-Member']          = Get-Command -Name Add-Member          -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
+        $script:SafeCommands['New-Object']          = & (Pester\SafeGetCommand) -Name New-Object          -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
+        $script:SafeCommands['Select-Object']       = & (Pester\SafeGetCommand) -Name Select-Object       -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
+        $script:SafeCommands['Export-ModuleMember'] = & (Pester\SafeGetCommand) -Name Export-ModuleMember -Module Microsoft.PowerShell.Core    -CommandType Cmdlet
+        $script:SafeCommands['Add-Member']          = & (Pester\SafeGetCommand) -Name Add-Member          -Module Microsoft.PowerShell.Utility -CommandType Cmdlet
 
         function EnterDescribe([string]$Name)
         {

Pester.psd1

@@ -46,7 +46,8 @@ FunctionsToExport = @(
     'AfterAll'
     'Get-MockDynamicParameters',
     'Set-DynamicParameterVariables',
-    'Set-TestInconclusive'
+    'Set-TestInconclusive',
+    'SafeGetCommand'
 )
 
 # # Cmdlets to export from this module

Pester.psm1

@@ -13,6 +13,10 @@ else
     $outNullModule = 'Microsoft.PowerShell.Utility'
 }
 
+# Tried using $ExecutionState.InvokeCommand.GetCmdlet() here, but it does not trigger module auto-loading the way
+# Get-Command does.  Since this is at import time, before any mocks have been defined, that's probably acceptable.
+# If someone monkeys with Get-Command before they import Pester, they may break something.
+
 $script:SafeCommands = @{
     'Add-Member'          = Get-Command -Name Add-Member          -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet -ErrorAction Stop
     'Add-Type'            = Get-Command -Name Add-Type            -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet -ErrorAction Stop
@@ -21,6 +25,7 @@ $script:SafeCommands = @{
     'ForEach-Object'      = Get-Command -Name ForEach-Object      -Module Microsoft.PowerShell.Core       -CommandType Cmdlet -ErrorAction Stop
     'Format-Table'        = Get-Command -Name Format-Table        -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet -ErrorAction Stop
     'Get-ChildItem'       = Get-Command -Name Get-ChildItem       -Module Microsoft.PowerShell.Management -CommandType Cmdlet -ErrorAction Stop
+    'Get-Command'         = Get-Command -Name Get-Command         -Module Microsoft.PowerShell.Core       -CommandType Cmdlet -ErrorAction Stop
     'Get-Content'         = Get-Command -Name Get-Content         -Module Microsoft.PowerShell.Management -CommandType Cmdlet -ErrorAction Stop
     'Get-Date'            = Get-Command -Name Get-Date            -Module Microsoft.PowerShell.Utility    -CommandType Cmdlet -ErrorAction Stop
     'Get-Item'            = Get-Command -Name Get-Item            -Module Microsoft.PowerShell.Management -CommandType Cmdlet -ErrorAction Stop
@@ -434,6 +439,16 @@ function Get-ScriptBlockScope
     [scriptblock].GetProperty('SessionStateInternal', $flags).GetValue($ScriptBlock, $null)
 }
 
+function SafeGetCommand
+{
+    <#
+        .SYNOPSIS
+        This command is used by Pester's Mocking framework.  You do not need to call it directly.
+    #>
+
+    return $script:SafeCommands['Get-Command']
+}
+
 $snippetsDirectoryPath = "$PSScriptRoot\Snippets"
 if ((& $script:SafeCommands['Test-Path'] -Path Variable:\psise) -and
     ($null -ne $psISE) -and
@@ -447,3 +462,4 @@ if ((& $script:SafeCommands['Test-Path'] -Path Variable:\psise) -and
 & $script:SafeCommands['Export-ModuleMember'] New-Fixture, Get-TestDriveItem, Should, Invoke-Pester, Setup, InModuleScope, Invoke-Mock
 & $script:SafeCommands['Export-ModuleMember'] BeforeEach, AfterEach, BeforeAll, AfterAll
 & $script:SafeCommands['Export-ModuleMember'] Get-MockDynamicParameters, Set-DynamicParameterVariables
+& $script:SafeCommands['Export-ModuleMember'] SafeGetCommand