Cursor rule

1---
2globs: **/*.spec.ts, **/*.test.ts, vitest.config.ts, packages/**/vitest.config.ts
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5## Testing (Vitest)
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7- **Goal**: Fast, reliable tests that validate behavior at the event and DB boundary, not implementation details.
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9### General Guidelines
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11- Use **Vitest** consistently; avoid mixing in Jest-only APIs.
12- Prefer:
13  - Clear Arrange–Act–Assert structure.
14  - One behavior/assertion cluster per test.
15  - Descriptive test names tied to domain language (e.g. "message query returns latest by ID").
16- Avoid:
17  - Sleeping or relying on real timeouts unless absolutely necessary.
18  - Network calls to real Telegram or external APIs; use mocks or fixtures instead.
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20### Core & DB Tests
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22- For `packages/core`:
23  - Test at the level of events and side effects (DB writes, emitted events), not private helpers.
24  - Use `setDbInstanceForTests` and/or in-memory PGlite where appropriate to isolate tests from production DBs.
25- For DB-related behavior:
26  - Prefer migrations + schema fixtures over ad‑hoc `CREATE TABLE` statements inside tests.
27  - Clean up state between tests; do not rely on test ordering.
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29### Client & Web Tests
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31- For `packages/client`:
32  - Focus on verifying that specific inputs/events produce the correct store updates and outgoing events.
33  - Mock `CoreContext` or WebSocket layers rather than hitting real servers.
34- For `apps/web`:
35  - Keep component tests focused and shallow where possible.
36  - Only write more integrated UI tests when they provide clear regression protection.
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