E2e Regression Async Generators

End-to-end regression tests for async generator copy logic

Trigger

When a code change touches copy logic inside an async generator path, prefer end-to-end tests that consume the full generator and assert specific values, not unit tests of private methods that hand-simulate the copy.

Triggers

• async generator
• copy logic
• done chunk
• RAGEngine.query
• regression test
• integration bug
• unit test gap

Required Procedure

• Drive the real production async generator path end-to-end (e.g., engine.query(...)).
• Consume the full async generator output; do not short-circuit after the first yield.
• Assert specific values on the emitted payload, not just key presence.
• For copy logic, verify the copied value matches the source value resolved by the production path.
• Ensure the regression test fails when the production copy logic is removed or broken.

Example

Canonical pattern: backend/tests/test_prompt_ab_variants.py::TestDoneMsgABKeysE2E

Forbidden Shortcuts

• Do not hand-simulate the copy step in a test of a private helper and assert the same assignment.
• Do not assert only key presence when value correctness is the actual contract.
• Do not stop consuming the generator early unless the test explicitly targets an early-stage behavior.

Delegation Template

When delegating a task affected by this skill, include:

SKILLS: file:.opencode/skills/generated/e2e-regression-async-generators/SKILL.md

Reviewer Checks

• Verify each required action above appears in the diff.

Source Knowledge IDs

• 2274327e-4f6f-4a2f-b3eb-f1c915b14af2 — End-to-end tests that consume the full async generator catch integration bugs that unit tests of private methods miss.
• 584bad6d-c7ee-4486-8ad4-3c4ef319e5ff — Copy logic inside async generator paths must be verified end-to-end, not by unit-testing a private helper in isolation.