Always return to original CWD after running Pester

src/Main.ps1

@@ -633,6 +633,9 @@ function Invoke-Pester {
         $script:mockTable = @{}
         # todo: move mock cleanup to BeforeAllBlockContainer when there is any
         Remove-MockFunctionsAndAliases -SessionState $PSCmdlet.SessionState
+
+        # store CWD so we can revert any changes at the end
+        $initialPWD = $pwd.Path
     }
 
     end {
@@ -1214,6 +1217,9 @@ function Invoke-Pester {
             }
         }
 
+        # go back to original CWD
+        if ($null -ne $initialPWD) { & $SafeCommands['Set-Location'] -Path $initialPWD }
+
         # exit with exit code if we fail and even if we succeed, otherwise we could inherit
         # exit code of some other app end exit with it's exit code instead with ours
         $failedCount = $run.FailedCount + $run.FailedBlocksCount + $run.FailedContainersCount

tst/Pester.RSpec.ts.ps1

@@ -2427,4 +2427,23 @@ i -PassThru:$PassThru {
             $r.Containers[1].Blocks[0].Tests[0].ErrorRecord.TargetObject.Message | Verify-Equal "Skipped due to previous failure at 'a.b' and Run.SkipRemainingOnFailure set to 'Run'"
         }
     }
+
+    b 'Changes to CWD are reverted on exit' {
+        t 'PWD is equal before and after running Invoke-Pester' {
+            $beforePWD = $pwd.Path
+
+            $sb = {
+                Describe 'd' {
+                    It 'i' {
+                        Set-Location '../'
+                        1 | Should -Be 1
+                    }
+                }
+            }
+
+            $container = New-PesterContainer -ScriptBlock $sb
+            Invoke-Pester -Container $container -Output None
+            $pwd.Path | Verify-Equal $beforePWD
+        }
+    }
 }