On our test suite (big django app) it takes about 15s to collect tests. So much that we added a util using ripgrep to find the file and pass it as an argument to pytest when using `pytest -k <testname>`.
- Creating and migrating the test DB is slow. There is no shame in storing and committing a premigrated sqlite test DB generated upon release, it's often small in size and will save time for everyone.
- Stash your old migrations that nobody use anymore.
- Use python -X importtime and paste the result in an online viewer. Sometimes moving heavy imports to functions instead of the global scope will make individual tests slower, but collection will be faster.
- Use pytest-xdist
- Disable transactions / rollback on readonly tests. Ideally you want most of your non-inserting tests to work on the migrated/preloaded features in your sqlite DB.
We can enter into more details if you want, but the pre migrated DB + xdist alone allowed me to speedup tests on a huge project from 30m to 1m.
Another thing that can slow down pytest collection and bootstrap is how fixture are loaded. So reducing number or scope of fixtures may help too.
How much time actually goes by after you click "run test" (or run the equivalent cli command) until the test finished running?
Any projects using the jvm I've ever worked on (none of which were clojure, admittedly) have always taken at least 10-15s until the pre-phases were finished and the actual test setup began