pytest xdist

1import json
2
3import pytest
4from filelock import FileLock
5
6
7@pytest.fixture(scope="session")
8def session_data(tmp_path_factory, worker_id):
9    if worker_id == "master":
10        # not executing in with multiple workers, just produce the data and let
11        # pytest's fixture caching do its job
12        return produce_expensive_data()
13
14    # get the temp directory shared by all workers
15    root_tmp_dir = tmp_path_factory.getbasetemp().parent
16
17    fn = root_tmp_dir / "data.json"
18    with FileLock(str(fn) + ".lock"):
19        if fn.is_file():
20            data = json.loads(fn.read_text())
21        else:
22            data = produce_expensive_data()
23            fn.write_text(json.dumps(data))
24    return data
25