# `testing.FakeSession.tick`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `testing.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Method of [`testing.FakeSession`](testing.FakeSession.md) · stable · since 2.0.0

```ts
tick(dtMs: number): void;
```

Advances fake time by `dtMs`, running every timer due on the way in due order,
synchronously, the armed frame included (see above). Promise continuations run after it
returns: await between ticks. The clock starts at 0 when the session is made;
[`Frame.timeMs`](Frame.timeMs.md) is it plus `performance.now()` at that moment. `performance.now()` itself
doesn't follow `tick`, so a hook's `timeMs` compares with the app's own `performance.now()`
reading only until the first tick: a test whose app compares the two puts the app's
`performance.now()` on the fake's timeline with `now()`.

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `tick` names no product |
| 2. A precedent | not recorded: no ledger row (coverage.json) names this member or its owner |
| 3. Two apps, or labs | not recorded: no ledger row names this member or its owner |
| 4. The cheaper fix first | not recorded per member (Appendix B decides it per need) |