Added tests for get-service based on code coverage analysis (#4773)

* reformated test cases

* added whitespace to format the test cases

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

@@ -13,7 +13,7 @@
   }
 
   $testCases =
-    @{ data = $null; value = 'null' },
+    @{ data = $null          ; value = 'null' },
     @{ data = [String]::Empty; value = 'empty string' }
 
   Context 'Check null or empty value to the -Name parameter' {
@@ -28,6 +28,7 @@
       }
     }
   }
+
   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)
@@ -40,4 +41,53 @@
       }
     }
   }
+
+  It "GetServiceCommand can be used as API for '<parameter>' with '<value>'" -TestCases @(
+    @{ parameter = "DisplayName" ; value = "foo" },
+    @{ parameter = "Include"     ; value = "foo","bar" },
+    @{ parameter = "Exclude"     ; value = "bar","foo" },
+    @{ parameter = "InputObject" ; script = { Get-Service | Select-Object -First 1 } },
+    @{ parameter = "Name"        ; value = "foo","bar" },
+    @{ parameter = "ComputerName"; value = "bar","foo" }
+  ) {
+    param($parameter, $value, $script)
+    if ($script -ne $null) {
+      $value = & $script
+    }
+
+    $getservicecmd = [Microsoft.PowerShell.Commands.GetServiceCommand]::new()
+    $getservicecmd.$parameter = $value
+    $getservicecmd.$parameter | Should Be $value
+  }
+
+  It "Get-Service filtering works for '<script>'" -TestCases @(
+    @{ script = { Get-Service -DisplayName Net* }               ; expected = { Get-Service | Where-Object { $_.DisplayName -like 'Net*' } } },
+    @{ script = { Get-Service -Include Net* -Exclude *logon }   ; expected = { Get-Service | Where-Object { $_.Name -match '^net.*?(?<!logon)$' } } }
+    @{ script = { Get-Service -Name Net* | Get-Service }        ; expected = { Get-Service -Name Net* } },
+    @{ script = { Get-Service -Name "$(new-guid)*" }            ; expected = $null },
+    @{ script = { Get-Service -DisplayName "$(new-guid)*" }     ; expected = $null },
+    @{ script = { Get-Service -DependentServices -Name winmgmt }; expected = { (Get-Service -Name winmgmt).DependentServices } },
+    @{ script = { Get-Service -RequiredServices -Name winmgmt } ; expected = { (Get-Service -name winmgmt).RequiredServices } }
+  ) {
+    param($script, $expected)
+    $services = & $script
+    if ($expected -ne $null) {
+      $servicesCheck = & $expected
+    }
+    if ($servicesCheck -ne $null) {
+      Compare-object $services $servicesCheck | Out-String | Should BeNullOrEmpty
+    } else {
+      $services | Should BeNullOrEmpty
+    }
+  }
+
+  It "Get-Service fails for non-existing service using '<script>'" -TestCases @(
+    @{ script  = { Get-Service -Name (new-guid) -ErrorAction Stop}       ;
+       ErrorId = "NoServiceFoundForGivenName,Microsoft.PowerShell.Commands.GetServiceCommand" },
+    @{ script  = { Get-Service -DisplayName (new-guid) -ErrorAction Stop};
+       ErrorId = "NoServiceFoundForGivenDisplayName,Microsoft.PowerShell.Commands.GetServiceCommand" }
+  ) {
+    param($script,$errorid)
+    { & $script } | ShouldBeErrorId $errorid
+  }
 }