# Android WebView To run WPT on WebView on an Android device, some additional set-up is required. Currently, Android WebView support is experimental. ## Prerequisites Please check [Chrome for Android](chrome_android.md) for the common instructions for Android support first. Ensure you have a userdebug or eng Android build installed on the device. Install an up-to-date version of system webview shell: 1. Go to [chromium-browser-snapshots](https://commondatastorage.googleapis.com/chromium-browser-snapshots/index.html?prefix=Android/) 2. Find the subdirectory with the highest number and click it, this number can be found in the "Commit Position" column of row "LAST_CHANGE" (at bottom of page). 3. Download `chrome-android.zip` file and unzip it. 4. Install `SystemWebViewShell.apk`. 5. On emulator, system webview shell may already be installed by default. Then you may need to remove the existing apk: * Choose a userdebug build. * Run an emulator with [writable system partition from command line](https://chromium.googlesource.com/chromium/src/+/HEAD/docs/android_emulator.md/) If you have an issue with ChromeDriver version mismatch, try one of the following: * Try removing `_venv/bin/chromedriver` such that wpt runner can install a matching version automatically. Failing that, please check your environment path and make sure that no other ChromeDriver is used. * Download the [ChromeDriver binary](https://chromedriver.chromium.org/) matching your WebView's major version and specify it on the command line ``` ./wpt run --webdriver-binary ... ``` Configure host remap rules in the [webview commandline file](https://cs.chromium.org/chromium/src/android_webview/docs/commandline-flags.md?l=57): ``` adb shell "echo '_ --host-resolver-rules=\"MAP nonexistent.*.test ^NOTFOUND, MAP *.test 127.0.0.1\"' > /data/local/tmp/webview-command-line" ``` Ensure that `adb` can be found on your system's PATH. ## Running Tests Example command line: ```bash ./wpt run --test-type=testharness android_webview ``` * Note that there is no support for channel or automatic installation. The test will be run against the current WebView version installed on the device. * Reftests are not supported at the moment.