alt Hacker NewsHere's another example of unit tests for hash tables (and RB-trees and skiplists and…)
https://github.com/FRRouting/frr/blob/master/tests/lib/test_...
(this file is #include'd from another, with some #define set up:)
https://github.com/FRRouting/frr/blob/master/tests/lib/test_...
The "tribe" of C developers with distaste for the preprocessor will absolutely hate how this is written. But it works and caught real issues. It doesn't use an external fuzzing tool but rather a deterministic PRNG (see prng_* calls) to get a good mix of call combinations. Coverage analysis was done to make sure it reaches everywhere.
(disclaimer: I wrote this. And it did catch bugs. Also it really should have a lot of comments.)
If you are in a tribe not hating on pp-macros, you might find this approach for testing/debugging data structures (or even the surrounding pp-based "CTL"-like C templating idea or abstract ways of dealing with the BST zoo) interesting:
Essentially, you just write a very simple (some might say trivial) interactive command-shell that can include an auto-checking upon edit of (in that case tree) invariants keyed-off an environment variable. The only missing piece is some little tool to generate random inserts/deletes/etc.If the micro-shell has a pretty printer then it is easy to "replay" any failed series of edits with some "p" commands before & after invariant failures.