SqlServerDsc: Change in integration tests to speed up tests

[johlju]

Details of the scenario you tried and the problem that is occurring:
Integration tests uses the following two It-blocks.

It 'Should be able to call Get-DscConfiguration without throwing' {
    { Get-DscConfiguration -Verbose -ErrorAction Stop } | Should -Not -Throw
}

It 'Should have set the resource and all the parameters should match' {
    $currentConfiguration = Get-DscConfiguration

    $resourceCurrentState = $currentConfiguration | Where-Object -FilterScript {
        $_.ConfigurationName -eq $configurationName
    } | Where-Object -FilterScript {
        $_.ResourceId -eq $resourceId
    }`

    ...
}

The integration tests for resource SqlSetup runs Get-DscConfiguration a few times which impacts the time it take to pass the test run. We are getting close to the (AppVeyor) time limit of 60 minutes, currently around ~50 minutes.

I suggest that we change the integration tests to the following instead (if possible), saving one call to Get-DscConfiguration for each test.

It 'Should be able to call Get-DscConfiguration without throwing' {
    {
        $script:currentConfiguration = Get-DscConfiguration -Verbose -ErrorAction Stop
    } | Should -Not -Throw
}

It 'Should have set the resource and all the parameters should match' {
    $resourceCurrentState = $script:currentConfiguration | Where-Object -FilterScript {
        $_.ConfigurationName -eq $configurationName
    } | Where-Object -FilterScript {
        $_.ResourceId -eq $resourceId
    }`

    ...
}

The DSC configuration that is using the resource (as detailed as possible):
n/a

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