Great to see you doing red/green TDD Simon!

Passing tests in your repo are great documentation of the tool at a microscopic level. And rerunning tests only burns tokens on failures (since passed tests just print a dot) so it’s token efficient too.

Some other neat tricks:

- For greater efficiency configure your test runner to print nothing (not even a dot/filename) for test successes. Agents don’t need progress dots, only the exit code & failure details

- Have your agent implement a 10ms timeout per test. pytest has hooks to do this. The agent will see tests time out and mock out all I/O and third party code - why test what one assumes third parties tested already! Your test suite is CPU-bound without a shared database, has no shared data and no tests that interfere with or depend on each other, so tests can run in parallel.

That timeout trick is very neat!

I'm OK with longer running tests because I always have them run against a real database (often SQLite, sometimes PostgreSQL) and real files created in temporary directories but I can see how the time limit might be useful for tests that don't need those kind of components.