Fix flaky moto_server fixture by using an OS-assigned ephemeral port - #3759
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puchengy wants to merge 1 commit into
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Fix flaky moto_server fixture by using an OS-assigned ephemeral port#3759puchengy wants to merge 1 commit into
puchengy wants to merge 1 commit into
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The `moto_server` session fixture hardcoded port 5001 and pre-bound a socket to it purely to detect conflicts (added in apache#292). This is still flaky: when tests run in parallel (e.g. multiple CI jobs on a shared runner) or when a previous run leaves the port in TIME_WAIT, the pre-bind raises `OSError: [Errno 98] Address already in use`, failing the whole test session at fixture setup. Bind to port 0 instead so the OS assigns a free ephemeral port, and read the actual bound port back via moto's `get_host_and_port()`. This removes the collision and the now-unnecessary pre-bind check (and the `socket` import). The fixture return annotation is corrected to `Generator[...]` since it yields. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Rationale for this change
The
moto_serversession fixture intests/conftest.pyhardcodes port5001and pre-binds a socket to it purely to detect conflicts (added in #292). This is still flaky: when the test session runs on a shared/parallel CI runner, or when a previous run left the port inTIME_WAIT, the pre-bind raises and fails the entire test session at fixture setup:Bumping the port (as #292 did, 5000 → 5001) and failing fast doesn't remove the collision — it only surfaces it sooner.
This change binds to port
0so the OS assigns a free ephemeral port, then reads the actual bound port back via moto'sget_host_and_port(). That eliminates the collision entirely and removes the now-unnecessary pre-bind check (and thesocketimport). The fixture's return annotation is also corrected toGenerator[...]since ityields.Are these changes tested?
Yes — existing moto-backed tests continue to pass against the new fixture (e.g.
tests/catalog/test_glue.pyS3 tests, which consumemoto_endpoint_url). Verified locally thatThreadedMotoServer(port=0)starts,get_host_and_port()returns a real ephemeral port, serves requests, and stops cleanly.ruff check tests/conftest.pypasses.Are there any user-facing changes?
No. Test-infrastructure only.