Check Whether drive exists

function get-checkdrive($server)
{	
		write-verbose "check drive -started"
	    $check= 'D:\' # no escape 
		$testobj=get-wmiobject win32_volume -filter  "DriveLetter= 'D:'" -computername $server
		$caption= $testobj.Caption
		if($check -contains ($caption) )
		{ 
			$TotalGB=@{Name="Capacity(GB)";expression={[math]::round(($_.Capacity/1073741824),2)}}
			$FreeGB=@{Name="FreeSpace(GB)";expression={[math]::round(($_.FreeSpace /1073741824),2)}}
			$test=$testobj|Select Name , $TotalGB,$FreeGB	
		    write-verbose "check drive -Completed"
            return ($test)
        }
        else                
        { 
			write-output "$check doesnt exist"
        }
}

I have wriitten this script to check whether the D DRIVE exist or not. the script works fine but the problem is if D doesn't exist it doesn;t print drive doesnt exist instead print

@{Name=D: , Freespace(GB)=0 , Capacity(GB)=0). please help.