Add DHCP support to xDNSServerAddress - Fixes #113

[PlagueHO]

This PR adds support to use the xDNSServerAddress cmdlet to set DNS Server Addresses to be obtained from a DHCP server.

This PR also improves integration tests and should meet HQRM style guidelines. It also makes changes to support #176.

The changes in detail are:

• Added Get-DnsClientServerStaticAddress to NetworkingDsc.Common to return statically
  assigned DNS server addresses to support fix for issue 113.
• MSFT_xDNSserverAddress:
  • Added support for setting DNS Client to DHCP for issue 113.
  • Added new examples to show how to enable DHCP on DNS Client.
  • Improved integration test coverage to enable testing of multiple addresses and DHCP.
  • Converted exception creation to use common exception functions.
• MSFT_xDhcpClient:
  • Updated example to also cover setting DNS Client to DHCP.

This will resolve #113 and #211

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This change is 

[codecov-io]

Codecov Report

Merging #216 into dev will decrease coverage by <1%.
The diff coverage is 100%.

@@         Coverage Diff         @@
##            dev   #216   +/-   ##
===================================
- Coverage    96%    96%   -1%     
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  Files        17     17           
  Lines      1277   1276    -1     
===================================
- Hits       1229   1228    -1     
  Misses       48     48

[tysonjhayes]

Reviewed 11 of 15 files at r1, 4 of 4 files at r2.
Review status: all files reviewed at latest revision, 3 unresolved discussions.

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Modules/xNetworking/DSCResources/MSFT_xDNSServerAddress/MSFT_xDNSServerAddress.psm1, line 118 at r2 (raw file):

        ) -join '')

    # If address not passed, set to an empty array

Feeling kind of forgetful at the moment. We have a validatenotnullorempty, basically we expect this code to be hit if the parameter is not used at all correct?

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Modules/xNetworking/Examples/Resources/xDhcpClient/1-xDHCPClient_EnableDHCP.ps1, line 30 at r2 (raw file):

            AddressFamily  = 'IPv4'
        }
        

Looks like we have some blank spaces here.

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Modules/xNetworking/Modules/NetworkingDsc.Common/NetworkingDsc.Common.psm1, line 324 at r2 (raw file):

                -f $InterfaceAlias)

        # Return null to support ErrorAction Silently Continue

I haven't seen this before, so if we don't return something SilentlyContinue doesn't work?

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Comments from Reviewable

[PlagueHO]

Thank you so much for reviewing @tysonjhayes! 😁

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Review status: 13 of 14 files reviewed at latest revision, 3 unresolved discussions.

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Modules/xNetworking/DSCResources/MSFT_xDNSServerAddress/MSFT_xDNSServerAddress.psm1, line 118 at r2 (raw file):

Previously, tysonjhayes (Tyson J. Hayes) wrote…

Feeling kind of forgetful at the moment. We have a validatenotnullorempty, basically we expect this code to be hit if the parameter is not used at all correct?

That is correct. I originally had the parameter defaulted to an empty array, but this results in a $null rather than empty array object and also throws because of the ValidateNotnulOrEmpty() I also wanted to ensure that a blank string or array wasn't passed through - instead the parameter should be left out entirely if DHCP should be enabled on DNS.

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Modules/xNetworking/Examples/Resources/xDhcpClient/1-xDHCPClient_EnableDHCP.ps1, line 30 at r2 (raw file):

Previously, tysonjhayes (Tyson J. Hayes) wrote…

Looks like we have some blank spaces here.

Done.

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Modules/xNetworking/Modules/NetworkingDsc.Common/NetworkingDsc.Common.psm1, line 324 at r2 (raw file):

Previously, tysonjhayes (Tyson J. Hayes) wrote…

I haven't seen this before, so if we don't return something SilentlyContinue doesn't work?

This is because if you call Get-DnsClientServerStaticAddress with -EA SilentlyContinue with an adapter that does not exist then what actually happens is New-InvalidOperationException is called which throws an exception, but the exception is suppressed and control returns to the line after New-InvalidOperationException. The return $null prevents the cmdlet from continuing past this point. The New-InvalidOperationException cmdlet comes from over in PSDscResources.

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Comments from Reviewable

[PlagueHO]

Hi @tysonjhayes - I've completed the changes as per your comments 😁 Any chance you could look them over if you get a chance?

[tysonjhayes]

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Review status: 13 of 14 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[tysonjhayes]

Reviewed 1 of 15 files at r1, 1 of 1 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[PlagueHO]

@tysonjhayes - thank you heaps sir! Appreciate it 👍