diff --git a/PSSwagger/GeneratedHelpers.ps1 b/PSSwagger/GeneratedHelpers.ps1
index 30552cb..27cc989 100644
--- a/PSSwagger/GeneratedHelpers.ps1
+++ b/PSSwagger/GeneratedHelpers.ps1
@@ -50,13 +50,16 @@ function Get-AzSubscriptionId
     param()
 
     $AzureContext = & "Get-AzureRmContext" -ErrorAction Stop
-    if(Get-Member -InputObject $AzureContext.Subscription -Name SubscriptionId)
+    if($AzureContext)
     {
-        return $AzureContext.Subscription.SubscriptionId
-    }
-    else
-    {
-        return $AzureContext.Subscription.Id        
+        if(Get-Member -InputObject $AzureContext.Subscription -Name SubscriptionId)
+        {
+            return $AzureContext.Subscription.SubscriptionId
+        }
+        else
+        {
+            return $AzureContext.Subscription.Id        
+        }
     }
 }
 
diff --git a/PSSwagger/New-ServiceClient.ps1 b/PSSwagger/New-ServiceClient.ps1
new file mode 100644
index 0000000..1b84c90
--- /dev/null
+++ b/PSSwagger/New-ServiceClient.ps1
@@ -0,0 +1,110 @@
+Microsoft.PowerShell.Core\Set-StrictMode -Version Latest
+
+<#
+.DESCRIPTION
+   Creates Service Client object.
+
+.PARAMETER  FullClientTypeName
+    Client type full name.
+
+.PARAMETER  AddHttpClientHandler
+    Switch to determine whether the client type constructor expects the HttpClientHandler object.
+
+.PARAMETER  Credential
+    Credential is required for for creating the HttpClientHandler object.
+
+.PARAMETER  AuthenticationCommand
+    Command that should return a Microsoft.Rest.ServiceClientCredentials object that implements custom authentication logic. 
+
+.PARAMETER  AuthenticationCommandArgumentList
+    Arguments to the AuthenticationCommand, if any.
+
+.PARAMETER  HostOverrideCommand
+    Command should return a custom hostname string.
+    Overrides the default host in the specification.
+
+.PARAMETER  SubscriptionIdCommand
+    Custom command get SubscriptionId value.
+
+.PARAMETER  GlobalParameterHashtable
+    Global parameters to be set on client object.
+#>
+function New-ServiceClient {
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]
+        $FullClientTypeName,
+
+        [Parameter(Mandatory = $false)]
+        [switch]
+        $AddHttpClientHandler,
+
+        [Parameter(Mandatory = $false)]
+        [pscredential]
+        $Credential,
+
+        [Parameter(Mandatory = $true)]
+        [string]
+        $AuthenticationCommand,
+
+        [Parameter(Mandatory = $false)]
+        [Object[]]
+        $AuthenticationCommandArgumentList,
+
+        [Parameter(Mandatory = $false)]
+        [string]
+        $HostOverrideCommand,
+
+        [Parameter(Mandatory = $false)]
+        [string]
+        $SubscriptionIdCommand,
+
+        [Parameter(Mandatory = $false)]
+        [PSCustomObject]
+        $GlobalParameterHashtable
+    )
+
+    $ClientArgumentList = @()
+    $InvokeCommand_parameters = @{
+        ScriptBlock = [scriptblock]::Create($AuthenticationCommand)
+    }
+    if ($AuthenticationCommandArgumentList) {
+        $InvokeCommand_parameters['ArgumentList'] = $AuthenticationCommandArgumentList
+    }
+    $ClientArgumentList += Invoke-Command @InvokeCommand_parameters
+
+    if ($AddHttpClientHandler) {
+        $httpClientHandler = New-HttpClientHandler -Credential $Credential
+        $ClientArgumentList += $httpClientHandler
+    }
+    
+    $delegatingHandler = New-Object -TypeName System.Net.Http.DelegatingHandler[] -ArgumentList 0
+    $ClientArgumentList += $delegatingHandler
+
+    $Client = New-Object -TypeName $FullClientTypeName -ArgumentList $ClientArgumentList
+
+    if ($HostOverrideCommand) {
+        $Client.BaseUri = Invoke-Command -ScriptBlock [scriptblock]::Create($HostOverrideCommand)
+    }
+
+    if ($GlobalParameterHashtable) {
+        $GlobalParameterHashtable.GetEnumerator() | ForEach-Object {
+            if (Get-Member -InputObject $Client -Name $_.Key -MemberType Property) {
+                if ((-not $_.Value) -and ($_.Key -eq 'SubscriptionId')) {
+                    if($SubscriptionIdCommand) {
+                        $Client.SubscriptionId = Invoke-Command -ScriptBlock [scriptblock]::Create($SubscriptionIdCommand)
+                    }
+                    else {
+                        $Client.SubscriptionId = Get-AzSubscriptionId
+                    }
+                }
+                else {
+                    $Client."$($_.Key)" = $_.Value
+                }
+            }    
+        }
+    }
+
+    return $Client
+}
diff --git a/PSSwagger/PSSwagger.Constants.ps1 b/PSSwagger/PSSwagger.Constants.ps1
index 06b0d5c..1a4094e 100644
--- a/PSSwagger/PSSwagger.Constants.ps1
+++ b/PSSwagger/PSSwagger.Constants.ps1
@@ -53,6 +53,7 @@ $DynamicAssemblyGenerationCode
 `$allDllsPath = Join-Path -Path `$ClrPath -ChildPath '*.dll'
 Get-ChildItem -Path `$allDllsPath -File | ForEach-Object { Add-Type -Path `$_.FullName -ErrorAction SilentlyContinue }
 
+. (Join-Path -Path `$PSScriptRoot -ChildPath 'New-ServiceClient.ps1')
 . (Join-Path -Path `$PSScriptRoot -ChildPath 'GeneratedHelpers.ps1')
 
 `$allPs1FilesPath = Join-Path -Path `$PSScriptRoot -ChildPath '$GeneratedCommandsName' | Join-Path -ChildPath '*.ps1'
@@ -157,11 +158,49 @@ $constructFlattenedParameter = @'
 $functionBodyStr = @'
 
     `$ErrorActionPreference = 'Stop'
-    $securityBlock
 
-    $clientName = New-Object -TypeName $FullClientTypeName -ArgumentList $clientArgumentList$apiVersion
-    $overrideBaseUriBlock
-    $GlobalParameterBlock
+    `$NewServiceClient_params = @{
+        FullClientTypeName = '$FullClientTypeName'
+    }
+$(
+if($AuthenticationCommand){
+"
+    `$NewServiceClient_params['AuthenticationCommand'] = @'
+    $AuthenticationCommand
+`'@ "
+    if($AuthenticationCommandArgumentName){
+"
+    `$NewServiceClient_params['AuthenticationCommandArgumentList'] = `$$AuthenticationCommandArgumentName"
+    }
+}
+if($AddHttpClientHandler){
+"
+    `$NewServiceClient_params['AddHttpClientHandler'] = `$true
+    `$NewServiceClient_params['Credential']           = `$Credential"
+}
+if($hostOverrideCommand){
+"
+    `$NewServiceClient_params['HostOverrideCommand'] = @'
+    $hostOverrideCommand
+`'@"
+}
+if($GlobalParameters) {
+'
+    $GlobalParameterHashtable = @{} '
+    
+    foreach($parameter in $GlobalParameters) {
+"    
+    `$GlobalParameterHashtable['$parameter'] = `$null
+    if(`$PSBoundParameters.ContainsKey('$parameter')) {
+        `$GlobalParameterHashtable['$parameter'] = `$PSBoundParameters['$parameter']
+    }
+"
+    }
+"
+    `$NewServiceClient_params['GlobalParameterHashtable'] = `$GlobalParameterHashtable "
+}
+)
+    $clientName = New-ServiceClient @NewServiceClient_params
     $oDataExpressionBlock
     $parameterGroupsExpressionBlock
     $flattenedParametersBlock
@@ -174,16 +213,6 @@ $functionBodyStr = @'
     }
 '@
 
-$clientArgumentListNoHandler = "`$serviceCredentials,`$delegatingHandler"
-$clientArgumentListHttpClientHandler = "`$serviceCredentials,`$httpClientHandler,`$delegatingHandler"
-
-$securityBlockStr = @'
-`$serviceCredentials = $authFunctionCall
-    $azSubscriptionIdBlock
-    $httpClientHandlerCall
-    `$delegatingHandler = New-Object -TypeName System.Net.Http.DelegatingHandler[] 0
-'@
-
 $parameterSetBasedMethodStrIfCase = @'
 if ('$operationId' -eq `$PsCmdlet.ParameterSetName) {
 $additionalConditionStart$methodBlock$additionalConditionEnd
@@ -428,23 +457,6 @@ $createObjectStr = @'
     return `$Object
 '@
 
-$ApiVersionStr = @'
-
-    if(Get-Member -InputObject $clientName -Name 'ApiVersion' -MemberType Property)
-    {
-        $clientName.ApiVersion = "$infoVersion"
-    }
-'@
-
-$GlobalParameterBlockStr = @'
-    if(Get-Member -InputObject `$clientName -Name '$globalParameterName' -MemberType Property)
-    {
-        `$clientName.$globalParameterName = $globalParameterValue
-    }
-'@
-
-$HostOverrideBlock = '`$ResourceManagerUrl = $hostOverrideCommand`n    $clientName.BaseUri = `$ResourceManagerUrl'
-
 $GeneratedCommandsName = 'Generated.PowerShell.Commands'
 
 $FormatViewDefinitionStr = @'
diff --git a/PSSwagger/PSSwagger.psm1 b/PSSwagger/PSSwagger.psm1
index 0178318..81bdc62 100644
--- a/PSSwagger/PSSwagger.psm1
+++ b/PSSwagger/PSSwagger.psm1
@@ -612,9 +612,10 @@ function New-PSSwaggerModule
         -PSHeaderComment $PSHeaderComment
 
     $CopyFilesMap = [ordered]@{
-        'GeneratedHelpers.ps1'     = 'GeneratedHelpers.ps1'
+        'GeneratedHelpers.ps1'      = 'GeneratedHelpers.ps1'
         'Test-CoreRequirements.ps1' = 'Test-CoreRequirements.ps1'
         'Test-FullRequirements.ps1' = 'Test-FullRequirements.ps1'
+        'New-ServiceClient.ps1'     = 'New-ServiceClient.ps1'
     }
 
     if (-not $AssemblyFileName) {
diff --git a/PSSwagger/Paths.psm1 b/PSSwagger/Paths.psm1
index d0d52cf..4806794 100644
--- a/PSSwagger/Paths.psm1
+++ b/PSSwagger/Paths.psm1
@@ -425,7 +425,7 @@ function New-SwaggerPath
     $parametersToAdd = @{}
     $flattenedParametersOnPSCmdlet = @{}
     $parameterHitCount = @{}
-    $globalParameterBlock = ''
+    $globalParameters = @()
     $x_ms_pageableObject = $null
     foreach ($parameterSetDetail in $parameterSetDetails) {
         if ($parameterSetDetail.ContainsKey('x-ms-pageable') -and $parameterSetDetail.'x-ms-pageable' -and (-not $isNextPageOperation)) {
@@ -505,7 +505,7 @@ function New-SwaggerPath
                         $globalParameterValue = $parameterDetails.ConstantValue
                     }
                     
-                    $globalParameterBlock += [Environment]::NewLine + $executionContext.InvokeCommand.ExpandString($GlobalParameterBlockStr)
+                    $globalParameters += $globalParameterName
                 }
             }
 
@@ -609,24 +609,24 @@ function New-SwaggerPath
     }
 
     # Process security section
-    $azSubscriptionIdBlock = ""
-    $authFunctionCall = ""
-    $overrideBaseUriBlock = ""
-    $httpClientHandlerCall = ""
+    $SubscriptionIdCommand = ""
+    $AuthenticationCommand = ""
+    $AuthenticationCommandArgumentName = ''
+    $hostOverrideCommand = ''
+    $AddHttpClientHandler = $false
     $securityParametersToAdd = @()
     $PowerShellCodeGen = $SwaggerMetaDict['PowerShellCodeGen']
     if (($PowerShellCodeGen['ServiceType'] -eq 'azure') -or ($PowerShellCodeGen['ServiceType'] -eq 'azure_stack')) {
-        $azSubscriptionIdBlock = "`$subscriptionId = Get-AzSubscriptionId"
+        $SubscriptionIdCommand = 'Get-AzSubscriptionId'
     }
     if ($PowerShellCodeGen['CustomAuthCommand']) {
-        $authFunctionCall = $PowerShellCodeGen['CustomAuthCommand']
+        $AuthenticationCommand = $PowerShellCodeGen['CustomAuthCommand']
     }
     if ($PowerShellCodeGen['HostOverrideCommand']) {
         $hostOverrideCommand = $PowerShellCodeGen['HostOverrideCommand']
-        $overrideBaseUriBlock = $executionContext.InvokeCommand.ExpandString($HostOverrideBlock)
     }
     # If the auth function hasn't been set by metadata, try to discover it from the security and securityDefinition objects in the spec
-    if (-not $authFunctionCall) {
+    if (-not $AuthenticationCommand) {
         if ($FunctionDetails.ContainsKey('Security')) {
             # For now, just take the first security object
             if ($FunctionDetails.Security.Count -gt 1) {
@@ -674,11 +674,12 @@ function New-SwaggerPath
                     }
                     # If the service is specified to not issue authentication challenges, we can't rely on HttpClientHandler
                     if ($PowerShellCodeGen['NoAuthChallenge'] -and ($PowerShellCodeGen['NoAuthChallenge'] -eq $true)) {
-                        $authFunctionCall = 'Get-AutoRestCredential -Credential $Credential'
+                        $AuthenticationCommand = 'param([pscredential]$Credential) Get-AutoRestCredential -Credential $Credential'
+                        $AuthenticationCommandArgumentName = 'Credential'
                     } else {
                         # Use an empty service client credentials object because we're using HttpClientHandler instead
-                        $authFunctionCall = 'Get-AutoRestCredential'
-                        $httpClientHandlerCall = '$httpClientHandler = New-HttpClientHandler -Credential $Credential'
+                        $AuthenticationCommand = 'Get-AutoRestCredential'
+                        $AddHttpClientHandler = $true
                     }
                 } elseif ($type -eq 'apiKey') {
                     if (-not (Get-Member -InputObject $securityDefinition -Name 'name')) {
@@ -712,7 +713,8 @@ function New-SwaggerPath
                         Parameter = $credentialParameter
                         IsConflictingWithOperationParameter = $false
                     }
-                    $authFunctionCall = "Get-AutoRestCredential -APIKey `$APIKey -Location '$in' -Name '$name'"
+                    $AuthenticationCommand = "param([string]`$APIKey) Get-AutoRestCredential -APIKey `$APIKey -Location '$in' -Name '$name'"
+                    $AuthenticationCommandArgumentName = 'APIKey'
                 } else {
                     Write-Warning -Message ($LocalizedData.UnsupportedAuthenticationType -f ($type))
                 }
@@ -720,14 +722,9 @@ function New-SwaggerPath
         }
     }
 
-    if (-not $authFunctionCall) {
+    if (-not $AuthenticationCommand) {
         # At this point, there was no supported security object or overridden auth function, so assume no auth
-        $authFunctionCall = 'Get-AutoRestCredential'
-    }
-
-    $clientArgumentList = $clientArgumentListNoHandler
-    if ($httpClientHandlerCall) {
-        $clientArgumentList = $clientArgumentListHttpClientHandler
+        $AuthenticationCommand = 'Get-AutoRestCredential'
     }
 
     $nonUniqueParameterSets = @()
@@ -961,18 +958,22 @@ function New-SwaggerPath
     }
 
     $functionBodyParams = @{
-                                ParameterSetDetails = $parameterSetDetails
-                                ODataExpressionBlock = $oDataExpressionBlock
-                                ParameterGroupsExpressionBlock = $parameterGroupsExpressionBlock
-                                GlobalParameterBlock = $GlobalParameterBlock
-                                SwaggerDict = $SwaggerDict
-                                SwaggerMetaDict = $SwaggerMetaDict
-                                SecurityBlock = $executionContext.InvokeCommand.ExpandString($securityBlockStr)
-                                OverrideBaseUriBlock = $overrideBaseUriBlock
-                                ClientArgumentList = $clientArgumentList
-                                FlattenedParametersOnPSCmdlet = $flattenedParametersOnPSCmdlet
-                           }
-
+        ParameterSetDetails               = $parameterSetDetails
+        ODataExpressionBlock              = $oDataExpressionBlock
+        ParameterGroupsExpressionBlock    = $parameterGroupsExpressionBlock
+        SwaggerDict                       = $SwaggerDict
+        SwaggerMetaDict                   = $SwaggerMetaDict
+        AddHttpClientHandler              = $AddHttpClientHandler
+        HostOverrideCommand               = $hostOverrideCommand
+        AuthenticationCommand             = $AuthenticationCommand
+        AuthenticationCommandArgumentName = $AuthenticationCommandArgumentName
+        SubscriptionIdCommand             = $SubscriptionIdCommand
+        FlattenedParametersOnPSCmdlet     = $flattenedParametersOnPSCmdlet
+    }
+    if($globalParameters) {
+        $functionBodyParams['GlobalParameters'] = $globalParameters
+    }
+                           
     $pathGenerationPhaseResult = Get-PathFunctionBody @functionBodyParams
     $bodyObject = $pathGenerationPhaseResult.BodyObject
 
diff --git a/PSSwagger/SwaggerUtils.psm1 b/PSSwagger/SwaggerUtils.psm1
index dc4396d..1b01a69 100644
--- a/PSSwagger/SwaggerUtils.psm1
+++ b/PSSwagger/SwaggerUtils.psm1
@@ -1373,10 +1373,9 @@ function Get-PathFunctionBody
         [AllowEmptyString()]
         $ParameterGroupsExpressionBlock,
 
-        [Parameter(Mandatory=$true)]
-        [string]
-        [AllowEmptyString()]
-        $GlobalParameterBlock,
+        [Parameter(Mandatory=$false)]
+        [string[]]
+        $GlobalParameters,
 
         [Parameter(Mandatory=$true)]
         [PSCustomObject]
@@ -1386,22 +1385,29 @@ function Get-PathFunctionBody
         [PSCustomObject]
         $SwaggerMetaDict,
 
-        [Parameter(Mandatory=$true)]
+        [Parameter(Mandatory=$false)]
+        [switch]
+        $AddHttpClientHandler,
+
+        [Parameter(Mandatory=$false)]
         [string]
-        $SecurityBlock,
+        $HostOverrideCommand,
 
         [Parameter(Mandatory=$true)]
         [string]
-        [AllowEmptyString()]
-        $OverrideBaseUriBlock,
-        
-        [Parameter(Mandatory=$true)]
-        [PSCustomObject]
-        $FlattenedParametersOnPSCmdlet,
+        $AuthenticationCommand,
 
-        [Parameter(Mandatory=$true)]
+        [Parameter(Mandatory=$false)]
         [string]
-        $ClientArgumentList
+        $AuthenticationCommandArgumentName,
+
+        [Parameter(Mandatory=$false)]
+        [string]
+        $SubscriptionIdCommand,
+
+        [Parameter(Mandatory=$true)]
+        [PSCustomObject]
+        $FlattenedParametersOnPSCmdlet
     )
 
     Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState
@@ -1414,16 +1420,12 @@ function Get-PathFunctionBody
     $clientName = '$' + $Info['ClientTypeName']
     $NameSpace = $info.namespace
     $FullClientTypeName = $Namespace + '.' + $Info['ClientTypeName']
-    $apiVersion = $null
     $SubscriptionId = $null
     $BaseUri = $null
     $GetServiceCredentialStr = ''
     $AdvancedFunctionEndCodeBlock = ''
     $GetServiceCredentialStr = 'Get-AzServiceCredential'
 
-    # Expanding again expands $clientName
-    $GlobalParameterBlock = $executionContext.InvokeCommand.ExpandString($GlobalParameterBlock)
-    
     $parameterSetBasedMethodStr = ''
     foreach ($parameterSetDetail in $ParameterSetDetails) {
         # Responses isn't actually used right now, but keeping this when we need to handle responses per parameter set
diff --git a/README.md b/README.md
index 85d8412..ca889a0 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,9 @@ A PowerShell module with commands to generate the PowerShell commands for a give
 ## Customizing PowerShell Metadata
 - [PowerShell Extensions](/docs/extensions/readme.md)
 
+## Testing generated module
+- [Mocking New-ServiceClient utility](/docs/testing/NewServiceClient.md)
+
 ## Supported Platforms
 | Usage | Platforms |
 | ----------------| ------------------------------------- |
diff --git a/docs/testing/NewServiceClient.md b/docs/testing/NewServiceClient.md
new file mode 100644
index 0000000..4a37cb9
--- /dev/null
+++ b/docs/testing/NewServiceClient.md
@@ -0,0 +1,6 @@
+# Mocking New-ServiceClient utility function
+- Implement your own New-ServiceClient function with mock/customized functionality in MockedNewServiceClient.ps1
+- Either rename or backup the New-ServiceClient.ps1 file under generated module base folder.
+- Copy MockedNewServiceClient.ps1 to module base folder as New-ServiceClient.ps1 file.
+- Invoke your tests to validate the cmdlets from generated module.
+- Restore the original New-ServiceClient.ps1 under module base folder.