fix existing flakiness + cut runtime closes #533

moritz commented

2026-06-16 18:29:12 +02:00

Owner

Description of the implemented changes

The changes were:

Bugfixing
New Feature
Breaking Change
Refactoring

Fix the existing test-suite flakiness and reduce its runtime: remove blind Process.sleep waits, share duplicated fee/cycle fixtures, replace internal-state assertions with behavior assertions, fix a seed-dependent property-generator error, and — the root cause of the intermittent failures — eliminate a concurrent-create_member PostgreSQL deadlock by making three foreign keys deferrable.

What has been changed?

Share create_fee_type and create_cycle fixtures
Drop the dead per-process seeds-run guard
Assert rendered behavior instead of socket internals in the index view
Wait on observable state instead of blind sleeps
Build date-filter property bounds without a reject-filter
Make member/user foreign keys deferrable to avoid create_member deadlock
Assert member/user foreign keys are deferrable
Keep deadlock-prone member tests synchronous
Document create_member deadlock fix and async-test-safety

Definition of Done

Code Quality

No new technical depths
Linting passed
Documentation is added were needed

Accessibility

New elements are properly defined with html-tags
Colour contrast follows WCAG criteria
Aria labels are added when needed
Everything is accessible by keyboard
Tab-Order is comprehensible
All interactive elements have a visible focus

Testing

Tests for new code are written
All tests pass
axe-core dev tools show no critical or major issues

Additional Notes

Scope was expanded mid-review (backtrack review_loop → requirements): the flakiness root cause turned out to be a product-level concurrent-create_member deadlock, so the test-only constraint was lifted for one bounded change — the deferrable-FK migration. This deadlock is also a latent production risk under concurrent sign-ups.
Deadlock fix verified empirically: 0 deadlocks in 15 full-suite runs under maximum CPU contention, versus ~1/12 before; a deterministic test guards the constraint state (an in-process concurrent reproduction is infeasible under the Ecto sandbox).
The review loop ran to iteration 4, which was a clean confirming pass (converged, not a cap escalation).
The index-view commit (assert rendered behavior …) is a large diff (~314 lines) because it migrates many :sys.get_state assertions to rendered-behavior assertions in one file.

## Description of the implemented changes The changes were: - [x] Bugfixing - [ ] New Feature - [ ] Breaking Change - [ ] Refactoring Fix the existing test-suite flakiness and reduce its runtime: remove blind `Process.sleep` waits, share duplicated fee/cycle fixtures, replace internal-state assertions with behavior assertions, fix a seed-dependent property-generator error, and — the root cause of the intermittent failures — eliminate a concurrent-`create_member` PostgreSQL deadlock by making three foreign keys deferrable. ## What has been changed? - Share create_fee_type and create_cycle fixtures - Drop the dead per-process seeds-run guard - Assert rendered behavior instead of socket internals in the index view - Wait on observable state instead of blind sleeps - Build date-filter property bounds without a reject-filter - Make member/user foreign keys deferrable to avoid create_member deadlock - Assert member/user foreign keys are deferrable - Keep deadlock-prone member tests synchronous - Document create_member deadlock fix and async-test-safety ## Definition of Done ### Code Quality - [ ] No new technical depths - [x] Linting passed - [x] Documentation is added were needed ### Accessibility - [ ] New elements are properly defined with html-tags - [ ] Colour contrast follows WCAG criteria - [ ] Aria labels are added when needed - [ ] Everything is accessible by keyboard - [ ] Tab-Order is comprehensible - [ ] All interactive elements have a visible focus ### Testing - [x] Tests for new code are written - [x] All tests pass - [ ] axe-core dev tools show no critical or major issues ## Additional Notes - Scope was expanded mid-review (backtrack review_loop → requirements): the flakiness root cause turned out to be a product-level concurrent-`create_member` deadlock, so the test-only constraint was lifted for one bounded change — the deferrable-FK migration. This deadlock is also a latent production risk under concurrent sign-ups. - Deadlock fix verified empirically: 0 deadlocks in 15 full-suite runs under maximum CPU contention, versus ~1/12 before; a deterministic test guards the constraint state (an in-process concurrent reproduction is infeasible under the Ecto sandbox). - The review loop ran to iteration 4, which was a clean confirming pass (converged, not a cap escalation). - The index-view commit (`assert rendered behavior …`) is a large diff (~314 lines) because it migrates many `:sys.get_state` assertions to rendered-behavior assertions in one file.

moritz added 11 commits 2026-06-16 18:29:12 +02:00

test(membership-fees): share create_fee_type and create_cycle fixtures 18fb954f73

Replace the create_fee_type/create_cycle helpers duplicated across 18/8
membership-fee test files with a single shared definition in Mv.Fixtures,
reconciling the divergent local signatures (including the reversed
argument order) into one superset so behavior is unchanged.

test(seeds): drop the dead per-process seeds-run guard 3bd55fbfec

test(member-live): assert rendered behavior instead of socket internals in the index view ccd1f81e3e

Replace :sys.get_state assertions on the LiveView socket with assertions on
rendered output, so the tests pin user-visible behavior rather than internal
state; the few sites with no observable equivalent are kept and annotated.

test: wait on observable state instead of blind sleeps 655fd80524

Replace the fixed Process.sleep waits in the import, members-PDF and
field-visibility tests with event-based / bounded-poll waits on the
observable condition, removing a known flakiness vector.

test(member-live): build date-filter property bounds without a reject-filter cb54c2c46e

The bound-pair generator filtered out ~1/4 of generated values, so unlucky
seeds hit StreamData's FilterTooNarrowError under full property runs.
Construct an at-least-one-bound-set pair directly instead, preserving the
exact domain with no rejection.

fix(repo): make member/user foreign keys deferrable to avoid create_member deadlock ef94d2ef10

Concurrent create_member transactions took FK FOR KEY SHARE (MultiXact) locks
on shared rows across members/users/membership_fee_types and could form a
cross-transaction cycle, producing intermittent PostgreSQL deadlocks (40P01)
under load. Making the three foreign keys DEFERRABLE INITIALLY DEFERRED moves
the check to commit time and breaks the cycle, without weakening integrity
(NOT NULL and ON DELETE RESTRICT are unaffected).

test(repo): assert member/user foreign keys are deferrable 5e84c342b7

test(member-live): keep deadlock-prone member tests synchronous c0f40a13ce

These member/group/custom-field LiveView tests stay async: false. With the
foreign keys now deferrable the create_member deadlock no longer forces it, so
the rationale is updated: they remain synchronous as a deferred scope decision,
and index_groups_url_params/member_filter_component additionally have separate
async-isolation issues that must be fixed before they can run in parallel.

docs(testing): document create_member deadlock fix and async-test-safety 3d792e8b04

docs(changelog): record member-creation deadlock fix under Unreleased 6d7ece20a8

Merge branch 'main' into issue/mitgliederverwaltung-533

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84e1cf1cb8

# Conflicts:
#	test/mv_web/member_live/index_test.exs

moritz merged commit a629bfb617 into main

2026-06-16 18:30:14 +02:00

moritz deleted branch issue/mitgliederverwaltung-533

2026-06-16 18:30:14 +02:00

moritz referenced this pull request from a commit

2026-06-16 18:30:15 +02:00

Merge pull request 'fix existing flakiness + cut runtime closes #533' (#544) from issue/mitgliederverwaltung-533 into main

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fix existing flakiness + cut runtime closes #533 #544