Start-Sleep: add 'ms' alias to '-Milliseconds' (#4039)

src/Microsoft.PowerShell.Commands.Utility/commands/utility/StartSleepCommand.cs

@@ -54,6 +54,7 @@ namespace Microsoft.PowerShell.Commands
         /// </summary>
         [Parameter(Mandatory = true, ParameterSetName = "Milliseconds", ValueFromPipelineByPropertyName = true)]
         [ValidateRangeAttribute(0, int.MaxValue)]
+        [Alias("ms")]
         public int Milliseconds { get; set; }
 
         #endregion

test/powershell/Modules/Microsoft.PowerShell.Utility/Start-Sleep.Tests.ps1

@@ -9,6 +9,7 @@ Describe "Start-Sleep DRT Unit Tests" -Tags "CI" {
         Start-Sleep -Seconds 1
         $watch.Stop()
         $watch.ElapsedMilliseconds | Should BeGreaterThan 950
+        $watch.ElapsedMilliseconds | Should BeLessThan 1050
     }
 
     It "Should work properly when sleeping with Milliseconds" {
@@ -16,6 +17,15 @@ Describe "Start-Sleep DRT Unit Tests" -Tags "CI" {
         Start-Sleep -Milliseconds 1000
         $watch.Stop()
         $watch.ElapsedMilliseconds | Should BeGreaterThan 950
+        $watch.ElapsedMilliseconds | Should BeLessThan 1050
+    }
+
+    It "Should work properly when sleeping with ms alias" {
+        $watch = [System.Diagnostics.Stopwatch]::StartNew()
+        Start-Sleep -ms 1000
+        $watch.Stop()
+        $watch.ElapsedMilliseconds | Should BeGreaterThan 950
+        $watch.ElapsedMilliseconds | Should BeLessThan 1050
     }
 }