Rules/Test-ModuleHasAnAboutTopic.ps1

function Test-ModuleHasAnAboutTopic
{
    param(
    [Parameter(ParameterSetName='TestModuleInfo',Mandatory=$true,ValueFromPipeline=$true)]
    [Management.Automation.PSModuleInfo]
    $ModuleInfo
    )
    
    process {
        $aboutTopics =
            $ModuleInfo | 
                Split-Path | 
                Get-ChildItem -Filter "$(Get-Culture)" | 
                Get-ChildItem -Filter *.help.txt
        
        if (-not $aboutTopics) {        
            Write-Error "$ModuleInfo does not have an about topic"
        }
    }
}