Mycology is a Befunge-98 test suite that I developed side by side with the CCBI interpreter. It tests the full Befunge-98 specification as well as many extensions (fingerprints), with the only exception of the "
=" or "Execute" instruction, which I deemed too difficult to reliably test across platforms.
The 'Fungus' Funge-98 diagnostics tool was inadequate for my purposes, with inaccurate output and very little coverage. The Cats-Eye Technologies' Befunge Diagnostics has similar issues, and I didn't even have access to a copy of it at the time. (At the time of writing, it seems to still not be available online. Ask me for a copy if you're interested. I should also put one up here at some point.)
There used to be a comparison of test results here, with data on the interpreters of the time (). That page has been retired because that data is somewhat outdated by now and the community is no longer as active, so an update would not be very useful either. Mycology is fairly well-known in the community, to the point that Funge-98 implementers tend to mention whether they pass it or not, so users shouldn't need to worry about the details as long as they use an interpreter that claims Mycology-level standards conformance.
The full source code is available and can be viewed online at GitHub.