Add ValidateNullOrEmpty to -Name parameter of Get-Service (#2542)

* Adding validation to Get-Service -Name parameter

src/Microsoft.PowerShell.Commands.Management/commands/management/Service.cs

@@ -608,6 +608,7 @@ namespace Microsoft.PowerShell.Commands
         /// since it is optional for GetService and mandatory otherwise.
         /// </remarks>
         [Parameter(Position = 0, ParameterSetName = "Default", ValueFromPipelineByPropertyName = true, ValueFromPipeline = true)]
+        [ValidateNotNullOrEmpty()]
         [Alias("ServiceName")]
         public string[] Name
         {

test/powershell/Modules/Microsoft.PowerShell.Management/Get-Service.Tests.ps1

@@ -0,0 +1,43 @@
+Describe "Get-Service cmdlet tests" -Tags "CI" {
+  # Service cmdlet is currently working on windows only
+  # So skip the tests on non-Windows
+  BeforeAll {
+    $originalDefaultParameterValues = $PSDefaultParameterValues.Clone()
+    if ( -not $IsWindows ) {
+        $PSDefaultParameterValues["it:skip"] = $true
+    }
+  }
+  # Restore the defaults
+  AfterAll {
+      $global:PSDefaultParameterValues = $originalDefaultParameterValues
+  }
+
+  $testCases = 
+    @{ data = $null; value = 'null' },
+    @{ data = [String]::Empty; value = 'empty string' }
+
+  Context 'Check null or empty value to the -Name parameter' {
+    It 'Should throw if <value> is passed to -Name parameter' -TestCases $testCases {
+      param($data)
+      try {
+        $null = Get-Service -Name $data -ErrorAction Stop
+        throw 'Expected error on previous command'
+      }
+      catch {
+        $_.FullyQualifiedErrorId | Should Be 'ParameterArgumentValidationError,Microsoft.Powershell.Commands.GetServiceCommand'
+      }
+    }
+  }
+  Context 'Check null or empty value to the -Name parameter via pipeline' {
+    It 'Should throw if <value> is passed through pipeline to -Name parameter' -TestCases $testCases {
+      param($data)
+      try {
+        $null = Get-Service -Name $data -ErrorAction Stop
+        throw 'Expected error on previous command'
+      }      
+      catch {
+        $_.FullyQualifiedErrorId | Should Be 'ParameterArgumentValidationError,Microsoft.Powershell.Commands.GetServiceCommand'
+      }
+    }
+  }
+}