Add -Name, -NoUserOverrides and -ListAvailable parameters to Get-Cult…

…ure cmdlet (PowerShell#7702)

Add new parameters in Get-Culture cmdlet:
-Name - to allow retrieving a specific culture
-NoUserOverrides - ignore user changes for current culture
-ListAvalable - to allow retrieving all cultures supported on the platform

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

@@ -1,23 +1,124 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System;
+using System.Collections.Generic;
+using System.Globalization;
 using System.Management.Automation;
 
 namespace Microsoft.PowerShell.Commands
 {
     /// <summary>
-    /// Returns the thread's current culture.
+    /// Returns:
+    ///     - the thread's current culture
+    ///     - culture by name
+    ///     - list of all supported cultures.
     /// </summary>
-    [Cmdlet(VerbsCommon.Get, "Culture", HelpUri = "https://go.microsoft.com/fwlink/?LinkID=113312")]
+    [Cmdlet(VerbsCommon.Get, "Culture", DefaultParameterSetName = CurrentCultureParameterSet, HelpUri = "https://go.microsoft.com/fwlink/?LinkID=113312")]
     [OutputType(typeof(System.Globalization.CultureInfo))]
     public sealed class GetCultureCommand : PSCmdlet
     {
+        private const string CurrentCultureParameterSet = "CurrentCulture";
+        private const string NameParameterSet = "Name";
+        private const string ListAvailableParameterSet = "ListAvailable";
+
+        /// <summary>
+        /// Gets or sets culture names for which CultureInfo values are returned.
+        /// Empty string matches Invariant culture.
+        /// </summary>
+        [Parameter(ParameterSetName = NameParameterSet, Position = 0, ValueFromPipeline = true)]
+        [ValidateSet(typeof(ValidateCultureNamesGenerator))]
+        [ValidateNotNull]
+        public string[] Name { get; set; }
+
+        /// <summary>
+        /// Gets or sets a switch to return current culture with user overrides (by default).
+        /// With the switch on, we return current culture without user overrides.
+        /// </summary>
+        [Parameter(ParameterSetName = CurrentCultureParameterSet)]
+        [Parameter(ParameterSetName = NameParameterSet)]
+        public SwitchParameter NoUserOverrides { get; set; }
+
+        /// <summary>
+        /// Gets or sets a switch to list all available cultures.
+        /// </summary>
+        [Parameter(ParameterSetName = ListAvailableParameterSet)]
+        public SwitchParameter ListAvailable { get; set; }
+
         /// <summary>
-        /// Output the current Culture info object.
+        /// Output:
+        ///     - the thread's current culture
+        ///     - culture by name
+        ///     - list of all supported cultures.
         /// </summary>
-        protected override void BeginProcessing()
+        protected override void ProcessRecord()
+        {
+            CultureInfo ci;
+
+            switch (ParameterSetName)
+            {
+                case CurrentCultureParameterSet:
+                    if (NoUserOverrides)
+                    {
+                        ci = CultureInfo.GetCultureInfo(Host.CurrentCulture.Name);
+                    }
+                    else
+                    {
+                        ci = Host.CurrentCulture;
+                    }
+
+                    WriteObject(ci);
+
+                    break;
+                case NameParameterSet:
+                    try
+                    {
+                        foreach (var cultureName in Name)
+                        {
+                            if (!NoUserOverrides && string.Equals(cultureName, Host.CurrentCulture.Name, StringComparison.CurrentCultureIgnoreCase))
+                            {
+                                ci = Host.CurrentCulture;
+                            }
+                            else
+                            {
+                                ci = CultureInfo.GetCultureInfo(cultureName);
+                            }
+
+                            WriteObject(ci);
+                        }
+                    }
+                    catch (CultureNotFoundException exc)
+                    {
+                        WriteError(new ErrorRecord(exc, "ItemNotFoundException", ErrorCategory.ObjectNotFound, Name));
+                    }
+
+                    break;
+                case ListAvailableParameterSet:
+                    foreach (var cultureInfo in CultureInfo.GetCultures(CultureTypes.AllCultures))
+                    {
+                        WriteObject(cultureInfo);
+                    }
+
+                    break;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Get list of valid culture names for ValidateSet attribute.
+    /// </summary>
+    public class ValidateCultureNamesGenerator : IValidateSetValuesGenerator
+    {
+        string[] IValidateSetValuesGenerator.GetValidValues()
         {
-            WriteObject(Host.CurrentCulture);
+            var cultures = CultureInfo.GetCultures(CultureTypes.AllCultures);
+            var result = new List<string>(cultures.Length);
+            foreach (var cultureInfo in cultures)
+            {
+                result.Add(cultureInfo.Name);
+            }
+
+            return result.ToArray();
         }
     }
 }

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

@@ -1,25 +1,72 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License.
-Describe "Get-Culture DRT Unit Tests" -Tags "CI" {
-    It "Should works proper with get-culture" {
-        $results = get-Culture
-        $results -is "System.Globalization.CultureInfo" | Should -BeTrue
-        $results[0].Name | Should -Be $PSCulture
-    }
-}
 
 Describe "Get-Culture" -Tags "CI" {
 
     It "Should return a type of CultureInfo for Get-Culture cmdlet" {
 
-	Get-Culture | Should -BeOfType CultureInfo
+        $culture = Get-Culture
+        $culture | Should -BeOfType [CultureInfo]
+        ($culture).EnglishName | Should -BeExactly $host.CurrentCulture.EnglishName
+
+        Get-Culture -NoUserOverrides | Should -BeOfType [CultureInfo]
+    }
+
+    It "Should have (Get-Culture).Name variable be equivalent to `$PSCulture" {
 
+        (Get-Culture).Name | Should -BeExactly $PsCulture
     }
 
-    It "Should have $ culture variable be equivalent to (Get-Culture).Name" {
+    It "Should return the specified culture with '-Name' parameter" {
 
-	(Get-Culture).Name | Should -Be $PsCulture
+        $ci = Get-Culture -Name ru-RU
+        $ci | Should -BeOfType [CultureInfo]
+        $ci.Name | Should -BeExactly "ru-RU"
 
+        $ci = Get-Culture -Name ru-RU -NoUserOverrides
+        $ci | Should -BeOfType [CultureInfo]
+        $ci.Name | Should -BeExactly "ru-RU"
     }
 
+    It "Should return specified cultures with '-Name' parameter" {
+
+        $ciArray = Get-Culture "", "ru-RU"
+        $ciArray | Should -HaveCount 2
+        $ciArray[0] | Should -BeOfType [CultureInfo]
+        $ciArray[0].EnglishName | Should -BeExactly "Invariant Language (Invariant Country)"
+
+        $ciArray[1] | Should -BeOfType [CultureInfo]
+        $ciArray[1].Name | Should -BeExactly "ru-RU"
+        $ciArray[1].EnglishName | Should -BeExactly "Russian (Russia)"
+    }
+
+    It "Should accept values from a pipeline for '-Name' parameter" {
+
+        $ciArray = "", "ru-RU" | Get-Culture
+        $ciArray | Should -HaveCount 2
+        $ciArray[0] | Should -BeOfType [CultureInfo]
+        $ciArray[0].EnglishName | Should -BeExactly "Invariant Language (Invariant Country)"
+        $ciArray[1] | Should -BeOfType [CultureInfo]
+        $ciArray[1].Name | Should -BeExactly "ru-RU"
+        $ciArray[1].EnglishName | Should -BeExactly "Russian (Russia)"
+    }
+
+    It "Should return the culture array with '-ListAvailable' parameter" {
+
+        $ciArray = Get-Culture -ListAvailable
+        $ciArray.Count | Should -BeGreaterThan 0
+        $ciArray[0] | Should -BeOfType [CultureInfo]
+    }
+
+    It "Should write an error on unsupported culture name" {
+
+        { Get-Culture -Name "abcdefghijkl" -ErrorAction Stop } | Should -PassThru -Throw -ErrorId "ParameterArgumentValidationError,Microsoft.PowerShell.Commands.GetCultureCommand"
+    }
+}
+
+Describe "`$PSCulture" -Tags "CI" {
+
+    It "Check `$PSCulture value" {
+        $PSCulture | Should -BeExactly $([System.Globalization.CultureInfo]::CurrentCulture.Name)
+    }
 }