Update 'Start-PSPester' to make it more user friendly (#7210)

- Make `Start-PSPester` call `Restore-Pester` automatically when needed,
- Make `-Path` a positional parameter for `Start-PSPester`.

build.psm1

@@ -981,11 +981,12 @@ function Publish-PSTestTools {
 function Start-PSPester {
     [CmdletBinding(DefaultParameterSetName='default')]
     param(
+        [Parameter(Position=0)]
+        [string[]]$Path = @("$PSScriptRoot/test/common","$PSScriptRoot/test/powershell"),
         [string]$OutputFormat = "NUnitXml",
         [string]$OutputFile = "pester-tests.xml",
         [string[]]$ExcludeTag = 'Slow',
         [string[]]$Tag = @("CI","Feature"),
-        [string[]]$Path = @("$PSScriptRoot/test/common","$PSScriptRoot/test/powershell"),
         [switch]$ThrowOnFailure,
         [string]$binDir = (Split-Path (Get-PSOptions -DefaultToNew).Output),
         [string]$powershell = (Join-Path $binDir 'pwsh'),
@@ -1001,24 +1002,9 @@ function Start-PSPester {
         [switch]$IncludeFailingTest
     )
 
-    $getModuleResults = Get-Module -ListAvailable -Name $Pester -ErrorAction SilentlyContinue
-    if (-not $getModuleResults)
+    if (-not (Get-Module -ListAvailable -Name $Pester -ErrorAction SilentlyContinue | Where-Object { $_.Version -ge "4.2" } ))
     {
-        Write-Warning @"
-Pester module not found.
-Restore the module to '$Pester' by running:
-    Restore-PSPester
-"@
-        return;
-    }
-
-    if (-not ($getModuleResults | Where-Object { $_.Version -ge "4.2" } )) {
-        Write-Warning @"
-No Pester module of version 4.2 and higher.
-Restore the required module version to '$Pester' by running:
-    Restore-PSPester
-"@
-        return;
+          Restore-PSPester
     }
 
     if ($IncludeFailingTest.IsPresent)

docs/testing-guidelines/testing-guidelines.md

@@ -108,14 +108,11 @@ Currently, we have a minuscule number of tests which are run by using xUnit.
 When working on new features or fixes, it is natural to want to run those tests locally before making a PR.
 Three helper functions are part of the build.psm1 module to help with that:
 
-* `Restore-PSPester` will restore Pester, which is needed to run `Start-PSPester`
 * `Start-PSPester` will execute all Pester tests which are run by the CI system
 * `Start-PSxUnit` will execute the available xUnit tests run by the CI system
 
 Our CI system runs these as well; there should be no difference between running these on your dev system, versus in CI.
 
-Make sure that you run `Restore-PSPester` before running `Start-PSPester`, or it will fail to run.
-
 When running tests in this way, be sure that you have started PowerShell with `-noprofile` as some tests will fail if the
 environment is not the default or has any customization.
 

test/powershell/README.md

@@ -5,9 +5,7 @@ document.
 
 ## Running Pester Tests
 
-First, restore the correct version of Pester using `Restore-PSPester`.
-
-Then, go to the top level of the PowerShell repository and run: `Start-PSPester`
+Go to the top level of the PowerShell repository and run: `Start-PSPester`
 inside a self-hosted copy of PowerShell.
 
 You can use `Start-PSPester -Tests SomeTestSuite*` to limit the tests run.