How can I use Pester to mock a cmdlet in which the module is not available?

Question

I am trying to write Pester tests for my Azure automation runbooks. The runbook script uses the Get-AutomationVariable cmdlet, and I am attempting to mock it via:

mock 'Get-AutomationVariable' {return "localhost:44300"} -ParameterFilter { $name -eq "host"}

which results in the error

CommandNotFoundException: The term 'Get-AutomationVariable' is not recognized as the name of a cmdlet, function, script file, or operable program.

Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

The use of the -ModuleName parameter does not seem appropriate as I am calling the method from a script not a module. Trying to provide a stub module results in the same error being thrown.

. "$here\$sut" "CN=teset, OU=Test" "CN=SubCA02, OU=Test"

Get-Module -Name RunbookMock | Remove-Module
New-Module -Name RunbookMock -ScriptBlock {
  function Get-AutomationVariable {
    [CmdLetBinding()]
    param(
      [string]$Name
    )

    ""
  }
  Export-ModuleMember Get-AutomationVariable
} | Import-Module -Force

describe 'Pin-Certificate' {
  it 'should add an entry to the pinned certificate list'{
    mock 'Get-AutomationVariable' { return "sastoken"} -ParameterFilter {  $Name -eq "StorageSasToken"} -
    mock 'Get-AutomationVariable' {return "localhost:44300"} -ParameterFilter { $name -eq "host"}
  }
}

Answer 1

Per the comments, your code should work. In the past I have just declared an empty function rather than a full module. E.g:

function MyScript {
    Get-FakeFunction
}

Describe 'Some Tests' {

    function Get-Fakefunction {}

    Mock 'Get-Fakefunction' { write-output 'someresult' }

    $Result = MyScript

    it 'should invoke Get-FakeFunction'{
        Assert-MockCalled 'Get-Fakefunction' -Times 1              
    }
    it 'should return someresult'{
        $Result | Should -Be 'someresult'
    }
}