When it comes to codec libraries, testing for correctness is essential, and EFR
is no exception.  There is a set of EFR encoder and decoder test sequences
published by ETSI in ts_100725v050200p0.zip (GSM 06.54), and our suite of tools
includes gsmefr-etsi-enc and gsmefr-etsi-dec test programs that operate on the
representation formats used by these test sequences.  Because these test
programs are based on libgsmefr EFR_encode_frame() and EFR_decode_frame()
functions, seeing gsmefr-etsi-enc produce output that matches official ETSI
*.cod files proves that libgsmefr encoder is correct, and seeing gsmefr-etsi-dec
produce output that matches official ETSI *.out files proves that libgsmefr
decoder is correct.

For debugging, we also have gsmefr-cod-parse and gsmefr-dec-parse utilities that
parse ETSI *.cod and *.dec file formats and dump their content in human-readable
form.