jerry-git
feature request: order tests by slowest-first
in long running test suites (especially with xdist), it's useful to run the slowest tests first so that you end up with better load. the following code seems to do so:
def pytest_collection_modifyitems(config, items):
try:
with open(".test_durations") as f:
s = f.read()
durations = json.loads(s)
except FileNotFoundError:
durations = {}
timings = {}
for item in items:
path, _, reqname = item.location
request_id = f"{path}::{reqname}"
timing = durations.get(request_id, None)
if timing is not None:
timings[item] = timing
meantime = sum(timings.values()) / len(timings)
# sort by highest time first
items.sort(key=lambda item: -timings.get(item, meantime))
but i was thinking it might be good for this to be available in the pytest-split plugin itself, so we don't need to add this same function across different projects.
alternatively, i was thinking publishing this as a plugin myself, if pytest-split does not want to add it.
Hey 👋 ! There's already support for different splitting algorithms, see
--splitting-algorithmCLI flag- currently supported algos in the README
- and their implementations in https://github.com/jerry-git/pytest-split/blob/master/src/pytest_split/algorithms.py
I believe what you are asking is actually quite close to "least duration" algo that already exists.
Happy to take a contribution which introduces "slowest first" splitting algorithm 🙂
yea these are interesting. the use case i am imagining is actually most useful with --splits 1 --group 1 because it reorders the items on the local worker. do you think "slowest first" makes sense with more splits?
If the main motivation is to optimise the usage with xdist, I guess there could be also use cases which prefer to have multiple test runner nodes (e.g. GHA workers). So, pytest-split for splitting the work to multiple nodes and then xdist for splitting the work inside each node.