A WiFi access point is not necessarily an IP-capable device (although many of them are, but for configuration, not communications, purposes).
Even if you do get the actual access point's IP address, how are you going to test the throughput? You could send ICMP Echo requests, but that will just give you instantaneous round-trip times, not throughput, and many IP devices, for security reasons, are configured to not respond to ICMP ECHO requests.