WebDriver Proxy for testing rich clients. It block certain calls until Angular is done updating the page under test.

Usage no npm install needed!

<script type="module">
  import blockingProxy from '';


Blocking Proxy Build Status

Blocking Proxy is a tool for adding functionality to WebDriver-based tests. It sits between your tests and the Selenium Server. For each WebDriver command, it runs a set of 'barriers' that will block forwarding the command to the Selenium server until some condition is met.

Because it interacts with WebDriver at the network level, Blocking Proxy can be used regardless of which language your tests are written in. See the example for a demonstration of using Blocking Proxy with WebDriver tests written in Python.

Although Blocking Proxy can handle multiple WebDriver sessions, it can not yet handle multiple concurrent clients. Thus, it's recommended to start a separate instance for each test process.


Blocking Proxy can be installed globally with npm install -g blocking-proxy. You can also use it by cloning this repo and running these commands:

npm install
webdriver-manager update && webdriver-manager start (in another terminal)
node ./built/lib/bin.js --seleniumAddress http://localhost:4444/wd/hub


Wait for Angular

When testing an Angular application, Blocking Proxy can block webdriver commands until Angular's change detection is finished, and thus make your tests less flaky.

Highlight Delay

If --highlightDelay <delayMS> is specified, Blocking Proxy will wait for the specified delay (in milliseconds) before executing click commands or sending keys. It will also highlight the element that is the target of the command.

Here's an example of highlight delay in action:

Highlight Delay

WebDriver logging

When --logDir <path> is set, Blocking Proxy will create a readable log of WebDriver commands at the specified path. The log will look something like this:

20:08:14.830 |    834ms | 37f13c | NewSession
20:08:15.674 |      4ms | 37f13c | SetTimeouts
20:08:15.681 |    578ms | 37f13c | Go http://localhost:8081/ng1/#/interaction
20:08:16.300 |    438ms | 37f13c | FindElement
    Using css selector \'.invalid\'
    ERROR: no such element

Each line shows the command that was executed and how long it took. For some commands, extra data or the response from WebDriver will be shown on following lines.


Formatting and lint

gulp format runs clang-format. gulp lint validates format and runs tslint.

Running tests

Unit tests live in spec/unit and can be run with npm test. Run npm run test:auto to automatically watch for changes and run unit tests.

Running e2e tests

Start webdriver

webdriver-manager update
webdriver-manager start

in another terminal, start the testapp

npm run testapp 

Start the proxy with

npm start

in yet another terminal, run the tests

npm run test:e2e