fix(appliance): make the Pester Copy-Item mock satisfy the script's copy guard

.github/workflows/scripts.yml

@@ -21,6 +21,10 @@ jobs:
       - name: Parse + analyze PowerShell
         shell: pwsh
         run: |
+          # Register the gallery if the runner image has not, then trust it. Set-PSRepository fails hard when
+          # PSGallery is not registered yet - an intermittent runner-image state that has flaked this job -
+          # so register-if-missing rather than assume it is there.
+          if (-not (Get-PSRepository -Name PSGallery -ErrorAction SilentlyContinue)) { Register-PSRepository -Default }
           Set-PSRepository PSGallery -InstallationPolicy Trusted
           Install-Module PSScriptAnalyzer -Force -Scope CurrentUser
           $dirs = 'appliance', 'installer/windows'
@@ -51,6 +55,7 @@ jobs:
       - name: Pester (Hyper-V import logic, cmdlets mocked)
         shell: pwsh
         run: |
+          if (-not (Get-PSRepository -Name PSGallery -ErrorAction SilentlyContinue)) { Register-PSRepository -Default }
           Set-PSRepository PSGallery -InstallationPolicy Trusted
           Install-Module Pester -MinimumVersion 5.5.0 -Force -Scope CurrentUser -SkipPublisherCheck
           Import-Module Pester

appliance/Import-DispatchAppliance.Tests.ps1

@@ -33,7 +33,12 @@ Describe 'Import-DispatchAppliance (unattended)' {
         Mock Set-VMMemory {}
         Mock Set-VMNetworkAdapterVlan {}
         Mock Start-VM {}
-        Mock Copy-Item {}
+        # Create the destination, rather than mocking the copy away to nothing. The script verifies the
+        # copy landed (Test-Path -PathType Leaf) before handing the path to New-VM - a real guard, since a
+        # silently failed copy would otherwise produce a VM pointed at a missing disk. A no-op mock made
+        # that guard throw on every test that got as far as the copy, which is why four of the six here have
+        # failed since they were written.
+        Mock Copy-Item { New-Item -ItemType File -Path $Destination -Force | Out-Null }
     }
 
     It 'keeps VM config + disk together under <storage>\<name>' {