helpers.ps1

function ConvertFrom-GlobalVariables {
    param(
        [hashtable]$ExpectedVariables,
        [string]$ScriptPath
    )

    $ExpectedVariables.Keys | ForEach-Object {
        Set-Variable -Name $_ -Value $ExpectedVariables[$_]
    }

    . $ScriptPath

    # this feels hacky, can't find a better way :(
    # find all variables set by the script that aren't in the parent or changed in the child
    # this will also include everything in $ExpectedVariables
    $_parent = @{}; $_local = @{}
    Get-Variable -Scope 1 | % { $_parent[$_.Name] = $_.Value }
    Get-Variable -Scope 0 | Where-Object {
        ($_parent[$_.Name] -ne $_.Value) -and
        ('MyInvocation','PSBoundParameters' -notcontains $_.Name) -and
        (-not $_.Name.StartsWith('_'))
    } | ForEach-Object {
        $_local[$_.Name] = $_.Value
    }
    $_local
}