xDnsRecordMx: Unit test missing Mock

[Sudman1]

Details of the scenario you tried and the problem that is occurring

Cannot throw Get-DnsServerResourceRecord Stub call, as it seems one of the MSFT_xDnsRecordMx\Set-TargetResource tests may not have mocked it.

Verbose logs showing the problem

...
  Describing MSFT_xDnsRecordMx\Set-TargetResource

    Context When managing MX type DNS record
      [-] Calls Add-DnsServerResourceRecord in the set method when Ensure is Present 98ms
        RuntimeException: Get-DnsServerResourceRecord: StubNotImplemented
        at Get-DnsServerResourceRecord, C:\Users\james\Documents\code\xDnsServer\tests\Unit\Stubs\DnsServer.psm1: line 5662
        at Set-TargetResource, C:\Users\james\Documents\code\xDnsServer\output\xDnsServer\0.0.1\DSCResources\MSFT_xDnsRecordMx\MSFT_xDnsRecordMx.psm1: line 163
        at <ScriptBlock>, C:\Users\james\Documents\code\xDnsServer\tests\Unit\MSFT_xDnsRecordMx.Tests.ps1: line 156
VERBOSE: Updating DNS record 'MX' for target 'mail.contoso.com.' in zone 'contoso.com' on 'localhost'.
...

Suggested solution to the issue

Verify that a mock for Get-DnsServerResourceRecord exists within the scope of the test (prior to being called) at line 156

[johlju]

The content of the stub should be changed from (which shows the missing mock as above)

Write-Verbose ('{0}: StubNotImplemented' -f $MyInvocation.MyCommand)

to

throw ('{0}: StubNotImplemented' -f $MyInvocation.MyCommand)

[johlju]

The resource have been deprecated and the unit test has been remove so we can add the throw back in the stub.