Ethernet emulation for some devices like Android phones' tethering use all-zero MAC addresses (which is okay since they don't actually pass Ethernet frames to other NICs). This results in a node ID of 0 if I'm currently connected to the Net via such a device. Which fails range checks in the corresponding tests.

RFC 4122 doesn't actually have any prohibitions of using a node ID of 0. Neither does IEEE 802.3 (or rather, whatever info I gathered on it since the standard's text is not freely available) assign any special meaning to an all-zero MAC address.

The patch also corrects the check call in test_windll_getnode since the tested function always generates UUID from a MAC address.