I don't think it is right to treat this as EOF. I haven't fully understood the problem (can you explain the format error encountered: what is expected, what is sent instead?), however, I notice that gzip itself also complains about an "unexpected EOF" error, so I don't think we should silently decompress the file. Producing an exception indicating the proper problem and including the data received so far in it would be more appropriate.

Also, can you provide an example file for the test suite that isn't copyrighted by somebody else?