detox timed out on CI: how to fix

TL;DR

Detox timeouts in CI come from slow emulators and over-strict synchronization. Extend timeouts for CI, calm the app's background activity, and make sure the device is actually fast enough.

Error

DetoxRuntimeError: Test timed out after 120000ms

Steps

1. Confirm the app builds and installs; timeouts after a successful install are runtime issues. Expected: build ruled out.
2. Raise testTimeout for CI in the Detox config. Expected: slow CI gets room.
3. Calm background activity: disable animations, network polling, and timers the test does not need. Expected: Detox sync engages faster.
4. Check device performance: emulators without acceleration are too slow. Expected: KVM/HAXM enabled.
5. Re-run the single test. Expected: green within the new timeout.

When to use

• Detox timeouts CI-only.
• After confirming the build works.

When not to use

• Build failures (different stage).
• Local timeouts (device or app issue).

Tool compatibility

• Detox 20.x; Android/iOS.

Variant phrasings

Detox test timeout

The general error; sync and speed are the levers.

Detox synchronization timeout

The sync-specific form; calm the app.

Why it happens

Detox waits for the app to idle. Busy apps on slow emulators never idle within the timeout.

Edge cases

• device.disableSynchronization() is a last resort; it trades determinism for speed.
• Long detox init on first run skews timings; warm the device.
• Split init and test timeouts; they are different knobs.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstcRP-3LehutiDNOaAk-acQ