Add -Shuffle switch to Get-Random command (#11093)

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

@@ -28,6 +28,7 @@ namespace Microsoft.PowerShell.Commands
 
         private const string RandomNumberParameterSet = "RandomNumberParameterSet";
         private const string RandomListItemParameterSet = "RandomListItemParameterSet";
+        private const string ShuffleParameterSet = "ShuffleParameterSet";
         private static readonly object[] _nullInArray = new object[] { null };
 
         private enum MyParameterSet
@@ -50,7 +51,8 @@ namespace Microsoft.PowerShell.Commands
                     {
                         _effectiveParameterSet = MyParameterSet.RandomListItem;
                     }
-                    else if (ParameterSetName.Equals(GetRandomCommand.RandomListItemParameterSet, StringComparison.OrdinalIgnoreCase))
+                    else if (ParameterSetName == GetRandomCommand.RandomListItemParameterSet
+                        || ParameterSetName == GetRandomCommand.ShuffleParameterSet)
                     {
                         _effectiveParameterSet = MyParameterSet.RandomListItem;
                     }
@@ -276,6 +278,7 @@ namespace Microsoft.PowerShell.Commands
         /// List from which random elements are chosen.
         /// </summary>
         [Parameter(ParameterSetName = RandomListItemParameterSet, ValueFromPipeline = true, Position = 0, Mandatory = true)]
+        [Parameter(ParameterSetName = ShuffleParameterSet, ValueFromPipeline = true, Position = 0, Mandatory = true)]
         [System.Management.Automation.AllowNull]
         [SuppressMessage("Microsoft.Performance", "CA1819:PropertiesShouldNotReturnArrays")]
         public object[] InputObject { get; set; }
@@ -283,12 +286,23 @@ namespace Microsoft.PowerShell.Commands
         /// <summary>
         /// Number of items to output (number of list items or of numbers).
         /// </summary>
-        [Parameter]
+        [Parameter(ParameterSetName = RandomNumberParameterSet)]
+        [Parameter(ParameterSetName = RandomListItemParameterSet)]
         [ValidateRange(1, int.MaxValue)]
         public int Count { get; set; } = 1;
 
         #endregion
 
+        #region Shuffle parameter
+
+        /// <summary>
+        /// Gets or sets whether the command should return all input objects in randomized order.
+        /// </summary>
+        [Parameter(ParameterSetName = ShuffleParameterSet, Mandatory = true)]
+        public SwitchParameter Shuffle { get; set; }
+
+        #endregion
+
         #region Cmdlet processing methods
 
         private double GetRandomDouble(double minValue, double maxValue)
@@ -491,8 +505,17 @@ namespace Microsoft.PowerShell.Commands
         protected override void ProcessRecord()
         {
             if (EffectiveParameterSet == MyParameterSet.RandomListItem)
+            {
+                if (ParameterSetName == ShuffleParameterSet)
                 {
                     // this allows for $null to be in an array passed to InputObject
+                    foreach (object item in InputObject ?? _nullInArray)
+                    {
+                        _chosenListItems.Add(item);
+                    }
+                }
+                else
+                {
                     foreach (object item in InputObject ?? _nullInArray)
                     {
                         // (3)
@@ -518,6 +541,7 @@ namespace Microsoft.PowerShell.Commands
                     }
                 }
             }
+        }
 
         /// <summary>
         /// This method implements the EndProcessing method for get-random command.

test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Random.Tests.ps1

@@ -156,6 +156,12 @@ Describe "Get-Random" -Tags "CI" {
         $randomNumber[6] | Should -BeNullOrEmpty
     }
 
+    It "Should return all the numbers for array of 1,2,3,5,8,13 in randomized order when the Shuffle switch is used" {
+        $randomNumber = Get-Random -InputObject 1, 2, 3, 5, 8, 13 -Shuffle
+        $randomNumber.Count | Should -Be 6
+        $randomNumber | Should -BeIn 1, 2, 3, 5, 8, 13
+    }
+
     It "Should return for a string collection " {
         $randomNumber = Get-Random -InputObject "red", "yellow", "blue"
         $randomNumber | Should -Be ("red" -or "yellow" -or "blue")
@@ -173,7 +179,7 @@ Describe "Get-Random" -Tags "CI" {
         $firstRandomNumber | Should -Not -Be $secondRandomNumber
     }
 
-    It "Should return the same number for hexadecimal number and regular number when the switch SetSeed it used " {
+    It "Should return the same number for hexadecimal number and regular number when the switch SetSeed is used " {
         $firstRandomNumber = Get-Random 0x07FFFFFFFF -SetSeed 20
         $secondRandomNumber = Get-Random 34359738367 -SetSeed 20
         $firstRandomNumber | Should -Be @secondRandomNumber