* Treat empty hidraw read as device removal (EOF)
When select() reports a hidraw fd as readable but os.read() returns
empty bytes, that's EOF per POSIX — the device has been removed.
Previously this was silently treated as no data, causing the listener
to loop indefinitely on a gone device instead of cleaning up.
* Fix test_ping_errors missing mocks for _read_input_buffer and write
The test was not mocking _read_input_buffer or write, so ping() would
call into real hidapi.read() with a fake handle (fd 1). The empty-read
EOF detection added in the previous commit made this consistently fail
by raising OSError → NoReceiver before reaching the mocked _read path.
Add the same mocks used by the adjacent test_request_errors.
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Co-authored-by: Peter F. Patel-Schneider <pfpschneider@gmail.com>
25865994cb