Yeah. They also created a open source test suite for S3 clones.
This is a set of unofficial Amazon AWS S3 compatibility tests, that can be useful to people implementing software that exposes an S3-like API. The tests use the Boto2 and Boto3 libraries.
Oh heh, a trip down the memory lane. I wrote the initial version of that, in an era where AWS docs did not match observed S3 behavior. The only way to make an S3-compatible API was to create a suite of over-the-network tests to run against both AWS S3 and radosgw.
We also had a little grammar-based fuzzer for S3 requests (really, any HTTP), but over the last 10+ years I've lost track of what happened to that code. That found some incompatibilities with allowed character sets etc too.
