xSQLServerAlwaysOnService: Returns IsHadrEnabled -eq $null

[johlju]

Details of the scenario you tried and the problem that is occurring:
Sometimes this row returns $null resulting in an exception. This most likely due to that the server has not been restarted after setup. I'm guessing, because I hit this issue during integration testing. And there I am suppressing reboot.
If we instead cast this row to a Boolean, it will always return false if it is false or $null.

https://github.com/PowerShell/xSQLServer/blob/dev/DSCResources/MSFT_xSQLServerAlwaysOnService/MSFT_xSQLServerAlwaysOnService.psm1#L45

The DSC configuration that is using the resource (as detailed as possible):
test run here: https://ci.appveyor.com/project/johlju/xsqlserver/build/6.0.851.0#L1652

Version of the Operating System, SQL Server and PowerShell the DSC Target Node is running:
n/a

What module (SqlServer or SQLPS) and which version of the module the DSC Target Node is running:
n/a

Version of the DSC module you're using, or 'dev' if you're using current dev branch:
Dev

[johlju]

Wrong link to error message. Above link is test run after testing casting to boolean. This is the correct url showing the error.
https://ci.appveyor.com/project/johlju/xsqlserver/build/6.0.848.0#L1658

[johlju]

The error message returned is

The status of property Server.IsHadrEnabled was neither $true or $false. Status is ''

Casting the return value to [System.Boolean] will make sure a $null value is never returned, and Test-TargetResource will always return $false if IsHadrEnabled property can't be read correctly.