test-discipline

name	test-discipline
description	Update tests when changing APIs — no exceptions
domain	quality
confidence	high
source	earned (Fenster/Hockney incident, test assertion sync violations)

Context

When APIs or public interfaces change, tests must be updated in the same commit. When test assertions reference file counts or expected arrays, they must be kept in sync with disk reality. Stale tests block CI for other contributors.

Patterns

• API changes → test updates (same commit): If you change a function signature, public interface, or exported API, update the corresponding tests before committing
• Test assertions → disk reality: When test files contain expected counts (e.g., EXPECTED_FEATURES, EXPECTED_SCENARIOS), they must match the actual files on disk
• Add files → update assertions: When adding docs pages, features, or any counted resource, update the test assertion array in the same commit
• CI failures → check assertions first: Before debugging complex failures, verify test assertion arrays match filesystem state
• Ordering invariants → behavior proof: When a test is guarding "X must happen before Y", prefer asserting the blocked-state outcome (no file rewrite, no DB rotation, refusal surfaced) over parsing source text or relying on substring order

Examples

✓ Correct:

• Changed auth API signature → updated auth.test.ts in same commit
• Added distributed-mesh.md to features/ → added 'distributed-mesh' to EXPECTED_FEATURES array
• Deleted two scenario files → removed entries from EXPECTED_SCENARIOS
• Replaced a source-order test with a same-root live-owner refusal test that proves the file and raw_imports stay unchanged

✗ Incorrect:

• Changed spawn parameters → committed without updating casting.test.ts (CI breaks for next person)
• Added built-in-roles.md → left EXPECTED_FEATURES at old count (PR blocked)
• Test says "expected 7 files" but disk has 25 (assertion staleness)
• Parsing collection.rs as text to prove a lease happens before a rewrite loop

Anti-Patterns

• Committing API changes without test updates ("I'll fix tests later")
• Treating test assertion arrays as static (they evolve with content)
• Assuming CI passing means coverage is correct (stale assertions can pass while being wrong)
• Leaving gaps for other agents to discover
• Locking sequencing behavior to source formatting, helper names, or substring order instead of observable state