device.launchApp() fails on Android emulator with exit status 251 for both app-under-test and system apps

[chikhanh123]

Mobilewright version

0.0.30

Operating system

MacOs

Target platform

Android

Device or simulator

simulator

Minimal reproduction

Summary

On Android emulator, device.launchApp() fails consistently in Mobilewright/mobilecli with exit status 251.
This reproduces not only with our app (kh.com.ibank.rdbuat) but also with a clean repro using Android Settings (com.android.settings) in a brand new project created via npx mobilewright init.

This suggests the issue is in the Android app launch path of Mobilewright/mobilecli, not in the target app or project setup.

Environment

Mobilewright: 0.0.30
@mobilewright/test: 0.0.30
@playwright/test: 1.58.2
Driver: default mobilecli
Android device id in Mobilewright: pixel
Device type: Android emulator
Android version: 14
Host: macOS
Mobilecli doctor detects the device successfully
Reproduction

Create a fresh project:
mkdir mobilewright-init-smoke
cd mobilewright-init-smoke
npx mobilewright init
npm init -y
npm install -D mobilewright@0.0.30 @mobilewright/test@0.0.30 @playwright/test@1.58.2 typescript@5.9.3
Use this config:
import { defineConfig } from 'mobilewright';

export default defineConfig({
platform: 'android',
bundleId: 'com.android.settings',
deviceId: 'pixel',
timeout: 30_000,
});
Use this test:
import { test, expect } from '@mobilewright/test';

test('launches Android Settings from init sample', async ({ device }) => {
const foregroundApp = await device.getForegroundApp();
expect(foregroundApp.bundleId).toBe('com.android.settings');
});
Run:
MW_PLATFORM=android MW_DEVICE_ID=pixel playwright test --config=mobilewright.config.ts

Actual behavior

Test fails during app launch with:

RpcError: failed to launch app on device pixel: failed to launch app com.android.settings: exit status 251
Output: bash arg: -p
bash arg: com.android.settings
bash arg: -c
bash arg: android.intent.category.LAUNCHER
bash arg: 1
args: [-p, com.android.settings, -c, android.intent.category.LAUNCHER, 1]
arg: "-p"
arg: "com.android.settings"
arg: "-c"
arg: "android.intent.category.LAUNCHER"
arg: "1"
data="com.android.settings"
data="android.intent.category.LAUNCHER"
** SYS_KEYS has no physical keys but with factor 2.0%.

Expected behavior

Expected Result

device.launchApp('com.android.settings') should foreground Android Settings successfully.

Additional context

Additional Notes

The same failure also happens with our app under test: kh.com.ibank.rdbuat
adb can launch the same apps successfully on the same emulator, for example:
adb -s emulator-5554 shell am start -S -n com.android.settings/.Settings
and for our app:

adb -s emulator-5554 shell am start -S -n kh.com.ibank.rdbuat/kh.com.ibank.rdb.MainActivity
So the app/emulator is healthy; the failure seems specific to Mobilewright/mobilecli’s Android launch mechanism.

Why this looks like a framework issue

Reproduces in a fresh npx mobilewright init project
Reproduces with a system app, not just a business app
Reproduces before any custom locator/test logic is involved
adb launch works on the same emulator

[gmegidish]

Hey @chikhanh123 , thanks for the bug report.

I tried to reproduce this and it worked for me. On Pixel 9 Pro emulator, I had this mobilewright.config.ts:

import { defineConfig } from 'mobilewright';

export default defineConfig({
  platform: 'android',
  timeout: 30_000,
});

and this example.test.ts:

import { test, expect } from '@mobilewright/test';

test('app launches and shows home screen', async ({ screen, device }) => {
  await device.launchApp("com.android.settings");
});

and it worked fine. You don't have to wait for foregroundApp, launchApp does this automatically unless requested.

I noticed that you're running "playwright" instead of "mobilewright". Can you please try "npx mobilewright test" and see if that solves the issue? if not, let's jump on a huddle. Join our slack and show me the problem. Let's debug together.

[chikhanh123]

Hi @gmegidish , thanks for checking this.

I tried again with a fresh Mobilewright project.

Steps to reproduce

Initialize a new project:

npm init mobilewright@latest

Then update mobilewright.config.ts:

import { defineConfig } from 'mobilewright';

export default defineConfig({
  platform: 'android',
  testDir: './tests',
  bundleId: 'com.android.settings',
  reporter: 'html',
  timeout: 10_000,
});

Run the test with Mobilewright CLI:

npx mobilewright test

Actual result

It still fails with exit status 251:

Running 1 test using 1 worker

  1) tests/example.spec.ts:6:5 › app launches and shows home screen

    RpcError: failed to launch app on device pixel: failed to launch app com.android.settings: exit status 251
    Output:   bash arg: -p
      bash arg: com.android.settings
      bash arg: -c
      bash arg: android.intent.category.LAUNCHER
      bash arg: 1
    args: [-p, com.android.settings, -c, android.intent.category.LAUNCHER, 1]
     arg: "-p"
     arg: "com.android.settings"
     arg: "-c"
     arg: "android.intent.category.LAUNCHER"
     arg: "1"
    data="com.android.settings"
    data="android.intent.category.LAUNCHER"
    ** SYS_KEYS has no physical keys but with factor 2.0%.

Manual ADB check

I also tried the underlying monkey command manually:

adb shell monkey -p com.android.settings -c android.intent.category.LAUNCHER 1

It fails with the same issue:

** SYS_KEYS has no physical keys but with factor 2.0%.
exit:251

But when I add --pct-syskeys 0, it works:

adb shell monkey --pct-syskeys 0 -p com.android.settings -c android.intent.category.LAUNCHER 1

Output:

Events injected: 1
exit:0

Environment

Mobilewright: 0.0.31
mobilecli: 0.3.70
Device ID: pixel
ADB serial: emulator-5554
Android model: sdk_gphone64_arm64
Android version: 14
Android Emulator: 36.1.9.0
macOS: 26.2 Apple Silicon
Node.js: 22.20.0

It looks like Mobilewright/mobilecli is launching Android apps with:

monkey -p <package> -c android.intent.category.LAUNCHER 1

On this emulator, that fails unless --pct-syskeys 0 is included.

Could Mobilewright/mobilecli add --pct-syskeys 0 when launching Android apps with monkey, or provide a launch option/workaround for this?

[gmegidish]

@chikhanh123 managed to reproduce! fix being released now.. I'll update in a bit.

[gmegidish]

mobile-next/mobilecli#223

[gmegidish]

Fixed and deployed! Please upgrade to version 0.0.32 and report back if that worked for you. Thanks again!! 🙏

[chikhanh123]

The new version 0.0.32 worked fine for me. Thank you!