The Onslip Automation Library

Remote-control any old Android or iOS WebView in a Playwright-inspired way

What it is

This is a small Node.js library that helps you to E2E test/automate/remote-control Android and iOS WebViews, including Capacitor- or Cordova-based hybrid applications.

The Onslip Automation API is heavily inspired by the Playwright Library and the aim is to provide a small but still very usable subset of that API. We strive to be as API compatible as we can for the subset that is supported, but since this is a completely separate code base, full compatibility can never be guaranteed.

Now, unlike Playwright's Android support — which requires version 87 or greater of the WebView — this library works with almost any version of the WebView, at least all the way down to the last Crosswalk release (which was based on Chromium 53)[^1]. We use it to automate Crosswalk on Android 4.1 and 6.0 devices, the default system WebView in Android 8 as well as iOS devices running iOS 12.4 and 15.4.

Additionally, we now also provide fixtures and matchers for Playwright Test, enabling integration/E2E testing of hybrid applications too.

How to use it

First, add this library as a dependency using your favorite package manager:

$ npm install -D @onslip/automation
$ pnpm add -D @onslip/automation
$ yarn add -D @onslip/automation

Second, ensure these dependencies are available:

• Android support requires the adb command to be installed and available in the path.
• iOS support needs ios_webkit_debug_proxy to be running and listening on port 9221. The iOS device management support uses
  • ideviceinstaller to install/uninstall apps;
  • idevicesyslog to read device logs; and
  • ios_instruments_client to start and stop iOS processes.

The first three iOS dependencies can be installed and activated from Homebrew with the following commands. ios_instruments_client must be compiled and copied to the path manually.

$ brew install ios-webkit-debug-proxy libimobiledevice ideviceinstaller
$ ios_webkit_debug_proxy

Finally, try this small example—or keep reading to see how to integrate with Playwright Test.

const { Device, AndroidDevice, findWebViewContexts, openWebView, pipeline } = require('@onslip/automation');
const { createWriteStream } = require('fs');
const { Readable } = require('stream');

const PROXY_PORT = 8885;

async function main(prog, deviceId) {
    const device = await Device.findDevice(deviceId);

    if (!device) {
        const devices = await Device.findDevices();
        throw `Usage: ${prog} ${devices.map((d) => d.id).join('|') || '<device>'}`;
    }

    console.log(`Checking for debuggable web view on device ${device}`);
    const [ webviewId ] = await device.findWebViews();

    console.log(`Found web view ${webviewId}; opening proxy port ${PROXY_PORT}`);
    const options = await device.bindWebView(webviewId, PROXY_PORT);

    console.log(`Looking for contexts`);
    const [ context ] = await findWebViewContexts(options);

    console.info(`Opening CDP connection via port ${options.port} to context ${context.id} <${context.url}>`);
    const page = await openWebView({...options, ctxId: context.id });

    console.info(`Starting automation of ${webviewId} on device ${device}`);
    page.setDebug(true);

    try {
        const lollipop = parseInt(await device.osVersion()) >= 5;
        const logLines = device instanceof AndroidDevice
            ? await device.collectLogs({ clear: !lollipop, historic: !lollipop, filterspecs: ['*:D'] })
            : await device.collectLogs();

        const divs = await page.locator('div').count();
        console.log(`There are ${divs} DIV elements in the web view!`);

        await page.locator('body').screenshot({ path: `${deviceId}.png` });
        console.log(`Saved a screenshot to ${deviceId}.png`);

        await pipeline(Readable.from(await logLines()), createWriteStream(`${deviceId}.log`));
        console.log(`Saved device logs to ${deviceId}.log`);
    } finally {
        await page.close();
    }
}

main(...process.argv.slice(1)).catch((err) => (console.error(err), 70)).then(process.exit);

Playwright Test

Playwright Test (or @playwright/test) a testing framework that uses the Playwright Library for end-to-end testing of web sites and web applications. Thanks to the fixtures and matchers provided by the Onslip Automation Library, you can now use Playwright Test to test your hybrid applications as well—on real devices or on emulators. Just import test and expect from @onslip/automation/test instead of @playwright/test and you're good to go.

import { test, expect } from '@onslip/automation/test';

test('has title', async ({ webApp }) => {
    // Expect a title "to contain" a substring.
    await expect(webApp.locator('title')).toHaveText(/Capacitor/);
});

test('get started link', async ({ webApp }) => {
    // Expect the "get started" button to link to https://capacitorjs.com.
    await expect(webApp.locator('.button', { hasText: 'Read more' })).toHaveAttribute('href', 'https://capacitorjs.com');
});

Please have a look at the included demo project for an example of how to launch an Android emulator, install a Capacitor hybrid app, and run tests on it.

[^1]: Using our fork of Capacitor together with Crosswalk, it's possible to run (and now automate or test) hybrid applications even on ancient devices running Android 4.1 from 2012.