Public/Test-IsGroupMember.ps1

function global:Test-IsGroupMember
{
        <#
            .EXTERNALHELP HelperFunctions.psm1-Help.xml
        #>

    
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true)]
        $user,
        [Parameter(Mandatory = $true)]
        $grp
    )
    
    begin
    {
        $strFilter = "(&(objectClass=Group)(name=" + $grp + "))"
        $objDomain = New-Object System.DirectoryServices.DirectoryEntry
        $objSearcher = New-Object System.DirectoryServices.DirectorySearcher
    }
    process
    {
        $objSearcher.SearchRoot = $objDomain
        $objSearcher.PageSize = 1000
        $objSearcher.Filter = $strFilter
        $objSearcher.SearchScope = "Subtree"
        
        $colResults = $objSearcher.FindOne()
        
        $objItem = $colResults.Properties
    }
    end
    {
        ([string]$objItem.member).contains($user)
    }
    
} #end function Test-IsGroupMember