Pester mocking azure cmdlets

Pester
1

Hello
I am trying out Pester for the unit testing. Is there better another way to test this or am I doing completely wrong?
Here is the function I need to test for unit testing.

Function Add-SubnetToVNet{
    Param(        
        [Parameter(Mandatory)]$SubnetName,        
        [Parameter(Mandatory)]$AddressPrefix,
        [Parameter(Mandatory)]$ResourceGroupName,
        [Parameter(Mandatory)]$VNetName
    )
    Process{
        $PSVnet = Get-AzVirtualNetwork -ResourceGroupName $ResourceGroupName -Name $VNetName
        Add-AzVirtualNetworkSubnetConfig -Name $SubnetName -AddressPrefix $AddressPrefix -VirtualNetwork $PSVnet        
        Set-AzVirtualNetwork -VirtualNetwork $PSVnet
    }
}

Here is the Pester test describe block.

Describe 'Add-SubnetToVNet'{
	Mock -CommandName 'Get-AzVirtualNetwork' -MockWith{
		$VnetObj = New-Object Microsoft.Azure.Commands.Network.Models.PSVirtualNetwork
		$VnetObj.Name              = 'VNet-Name'
		$VnetObj.ResourceGroupName = 'RG-VNet-Name'
		$VnetObj.Location          = 'uksouth'           
		return $VnetObj
	}
	Mock -CommandName 'Add-AzVirtualNetworkSubnetConfig'-MockWith{            
		$SubnetObj = New-Object Microsoft.Azure.Commands.Network.Models.PSSubnet
		$SubnetObj.Name = 'New-Subnet'
		$SubnetObj.Id   = '/subcriptions/random-guid-here/resourceGroups/RG-VNet-Name/Subnet-Name'
		$SubnetObj.ProvisioningState = 'Succeeded'
		$SubnetObj.AddressPrefix     = '10.7.0.0/24'
		return ($SubnetObj)
	}
	Mock -CommandName 'Set-AzVirtualNetwork' -MockWith{	
		$VnetObj.Subnets.Add($SubnetObj)          
		return $VnetObj
	}
	$TestVnet = Add-SubnetToVNet -SubnetName 'New-Subnet' -AddressPrefix '10.7.0.0/24' -ResourceGroupName 'RG-VNet-Name' -VNetName 'VNet-Name'
	It 'Should return a VNet with a subnet'{
		$TestVnet = Add-SubnetToVNet -SubnetName 'New-Subnet' -AddressPrefix '10.7.0.0/24' -ResourceGroupName 'RG-VNet-Name' -VNetName 'VNet-Name'            
		$TestVnet.Subnets | Should Not Be $null
	}
}

It said the virtual network was null and the test failed.
Thanks.

2

I have got this now. Just follow the pattern on the mock from this link.
https://4sysops.com/archives/mocking-with-pester-in-powershell-unit-testing/

3

Thanks for sharing the update/solution here.