Clean up the IPC named pipe on PowerShell exit (#12187)

test/powershell/Modules/Microsoft.PowerShell.Core/Get-PSHostProcessInfo.Tests.ps1

@@ -53,4 +53,49 @@ Describe "Get-PSHostProcessInfo tests" -Tag CI {
         $psProcess.Count | Should -BeGreaterOrEqual 1
         $psProcess.ProcessId | Should -Contain $powershell.id
     }
+
+    It "Verifies named pipe filepath get method" {
+        $pipeFilePath = (Get-PSHostProcessInfo -Id $pid).GetPipeNameFilePath()
+        $pipeFilePath | Should -Exist
+    }
+
+    It "Verifies named pipe filepath is removed on process exit" {
+        $aliveFile = Join-Path -Path $TestDrive -ChildPath 'AliveFileXXZZ.txt'
+        "" | Out-File -FilePath $aliveFile
+        $testfilePath = Join-Path -Path $TestDrive -ChildPath 'TestScriptXXZZ.ps1'
+        @'
+            param (
+                [string] $LiveFilePath
+            )
+
+            $count = 0
+            while ((Test-Path -Path $LiveFilePath) -and ($count++ -lt 60))
+            {
+                Start-Sleep -Milliseconds 500
+            }
+
+            exit
+'@ | Out-File -FilePath $testfilePath
+
+        # Create PowerShell process to monitor.
+        $psFileName = $IsWindows ? 'pwsh.exe' : 'pwsh'
+        $psPath = Join-Path -Path $PSHOME -ChildPath $psFileName
+        $psProc = Start-Process -FilePath $psPath -ArgumentList "-File $testfilePath -LiveFilePath $aliveFile" -PassThru
+        Wait-UntilTrue -sb {
+            (Get-PSHostProcessInfo -Id $psProc.Id) -ne $null
+        } -TimeoutInMilliseconds 5000 -IntervalInMilliseconds 250
+
+        # Verify named pipe file path.
+        $psNamedPipePath = (Get-PSHostProcessInfo -Id $psProc.Id).GetPipeNameFilePath()
+        $psNamedPipePath | Should -Exist
+
+        # Signal PowerShell test process to exit normally.
+        Remove-Item -Path $aliveFile -Force -ErrorAction Ignore
+        Wait-UntilTrue -sb {
+            (Test-Path -Path $psNamedPipePath) -eq $false
+        } -TimeoutInMilliseconds 5000 -IntervalInMilliseconds 250
+
+        # Verify named pipe file path is removed.
+        $psNamedPipePath | Should -Not -Exist
+    }
 }