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Selenium is an umbrella project encapsulating a variety of tools and libraries enabling web browser automation. Selenium specifically provides an infrastructure for the W3C WebDriver specification — a platform and language-neutral coding interface compatible with all major web browsers.

The project is made possible by volunteer contributors who've generously donated thousands of hours in code development and upkeep.

Selenium's source code is made available under the Apache 2.0 license.

This README is for developers interested in contributing to the project. For people looking to get started using Selenium, please check out our User Manual for detailed examples and descriptions, and if you get stuck, there are several ways to Get Help.


Please read [CONTRIBUTING.md]) before submitting your pull requests.


These are the requirements to create your own local dev environment to contribute to Selenium.

All Platforms



Several years ago Jim Evans published a great article on Setting Up a Windows Development Environment for the Selenium .NET Language Bindings; This article is out of date, but it includes more detailed descriptions and screenshots that some people might find useful.

Click to see Current Windows Setup Requirements #### Option 1: Automatic Installation from Scratch This script will ensure a complete ready to execute developer environment. (nothing is installed or set that is already present unless otherwise prompted) 1. Open Powershell as an Administrator 2. Execute: `Set-ExecutionPolicy Bypass -Scope Process -Force` to allow running the script in the process 3. Navigate to the directory you want to clone Selenium in, or the parent directory of an already cloned Selenium repo 4. Download and execute this script in the powershell terminal: [scripts/dev-environment-setup.ps1]` #### Option 2: Manual Installation 1. Allow running scripts in Selenium in general: ``` Set-ExecutionPolicy -ExecutionPolicy RemoteSigned ``` 2. Enable Developer Mode: ``` reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" /t REG_DWORD /f /v "AllowDevelopmentWithoutDevLicense" /d "1" ``` 3. Install [MSYS2](https://www.msys2.org/), which is an alternative shell environment that provides Unix-like commands * Add bin directory to PATH environment variable (e.g., "C:\tools\msys64\usr\bin") * Add bash.exe location as the BAZEL_SH environment variable (e.g., "C:\tools\msys64\usr\bin\bash.exe") 4. Install the latest version of [Visual Studio Community](https://visualstudio.microsoft.com/vs/community/) * Use the visual studio installer to modify and add the "Desktop development with C++" Workload * Add Visual C++ build tools installation directory location to BAZEL_VC environment variable (e.g. `"C:\Program Files\Microsoft Visual Studio\2022\Community\VC"`) * Add Visual C++ Build tools version to BAZEL_VC_FULL_VERSION environment variable (this can be discovered from the directory name in "$BAZEL_VC\Tools\MSVC\") 5. Add support for long file names (bazel has a lot of nested directories that can exceed default limits in Windows) * Enable Long Paths support with these 2 registry commands: ```shell reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Command Processor" /t REG_DWORD /f /v "DisableUNCCheck" /d "1" reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem" /t REG_DWORD /f /v "LongPathsEnabled" /d "1" ``` * Allow Bazel to create short name versions of long file paths: `fsutil 8dot3name set 0` * Set bazel output to C:/tmp instead of nested inside project directory: * Create a file selenium/.bazelrc.windows.local * Add "startup --output_user_root=C:/tmp" to the file

Alternative Dev Environments

If you want to contribute to the project, but do not want to set up your own local dev environment, there are two alternatives available.

Using GitPod

Rather than creating your own local dev environment, GitPod provides a ready to use environment for you.

Open in Gitpod

Using Dev Container

As an alternative you can build a Dev Container - basically a docker container - suitable for building and testing Selenium using the devcontainer.json in the .devcontainer directory. Supporting IDEs like VS Code or IntelliJ IDEA should point you to how such a container can be created.

Using Docker Image

You can also build a Docker image suitable for building and testing Selenium using the Dockerfile in the dev image directory.


Selenium is built using a common build tool called Bazel, to allow us to easily manage dependency downloads, generate required binaries, build and release packages, and execute tests; all in a fast, efficient manner. For a more detailed discussion, read Simon Stewart's article on Building Selenium

Often we wrap Bazel commands with our custom Rake wrapper. These are run with the ./go command.

The common Bazel commands are:

Each module that can be built is defined in a BUILD.bazel file. To execute the module you refer to it starting with a //, then include the relative path to the file that defines it, then :, then the name of the target. For example, the target to build the Grid is named executable-grid and it is defined in the 'selenium/java/src/org/openqa/selenium/grid/BAZEL.build' file. So to build the grid you would run: bazel build //java/src/org/openqa/selenium/grid:executable-grid.

The Bazel documentation has a handy guide for various shortcuts and all the ways to build multiple targets, which Selenium makes frequent use of.

To build everything for a given language:

bazel build //<language>/...

To build just the grid there is an alias name to use (the log will show where the output jar is located):

bazel build grid

To make things more simple, building each of the bindings is available with this ./go command

./go <language>:build




Most of the team uses Intellij for their day-to-day editing. If you're working in IntelliJ, then we highly recommend installing the Bazel IJ plugin which is documented on its own site.

To use Selenium with the IntelliJ Bazel plugin, import the repository as a Bazel project, and select the project view file from the scripts directory. ij.bazelproject for Mac/Linux and ij-win.bazelproject for Windows.


We also use Google Java Format for linting, so using the Google Java Formatter Plugin is useful; there are a few steps to get it working, so read their [configuration documentation]#intellij-jre-config). There is also an auto-formatting script that can be run: ./scripts/format.sh

Local Installation

While Selenium is not built with Maven, you can build and install the Selenium pieces for Maven to use locally by deploying to your local maven repository (~/.m2/repository), using:

./go java:install

Updating Dependencies

Dependencies are defined in the file maven_deps.bzl. To automatically update and pin new dependencies, run:

./go java:update


You can run Python code locally by updating generated files in the python directory using:

./go py:update

To install Selenium locally based on a specific commit, you can use:

./go py:install


Instead of using irb, you can create an interactive REPL with all gems loaded using: bazel run //rb:console

If you want to debug code, you can do it via debug gem:

  1. Add binding.break to the code where you want the debugger to start.
  2. Run tests with ruby_debug configuration: bazel test --config ruby_debug <test>.
  3. When debugger starts, run the following in a separate terminal to connect to debugger:
bazel-selenium/external/bundle/bin/rdbg -A

If you want to use RubyMine for development, you can configure it use Bazel artifacts:

  1. Open rb/ as a main project directory.
  2. Run bundle exec rake update as necessary to create up-to-date artifacts. If this does not work, run ./go rb:update from the selenium (parent) directory.
  3. In Settings / Languages & Frameworks / Ruby SDK and Gems add new Interpreter pointing to ../bazel-selenium/external/rules_ruby_dist/dist/bin/ruby.
  4. You should now be able to run and debug any spec. It uses Chrome by default, but you can alter it using environment variables secified in Ruby Testing section below.


To keep Carbo.Bazel.lock synchronized with Cargo.lock, run:

CARGO_BAZEL_REPIN=true bazel sync --only=crates


There are a number of bazel configurations specific for testing.

Common Options Examples

Here are examples of arguments we make use of in testing the Selenium code:


Selenium tests can be filtered by size:

These can be filtered using the test_size_filters argument like this:

bazel test //<language>/... --test_size_filters=small

Tests can also be filtered by tag like:

bazel test //<language>/... --test_tag_filters=this,-not-this


Click to see Java Test Commands To run unit tests: ```shell bazel test //java/... --test_size_filters=small ``` To run integration tests: ```shell bazel test //java/... --test_size_filters=medium ``` To run browser tests: ```shell bazel test //java/... --test_size_filters=large --test_tag_filters= ``` To run a specific test: ```shell bazel test //java/test/org/openqa/selenium/chrome:ChromeDriverFunctionalTest ```


Click to see JavaScript Test Commands To run the tests run: ```sh bazel test //javascript/node/selenium-webdriver:tests ``` You can use --test_env to pass in the browser name as SELENIUM_BROWSER. ```sh bazel test //javascript/node/selenium-webdriver:tests --test_env=SELENIUM_BROWSER=firefox ```


Click to see Python Test Commands Run unit tests with: ```shell bazel test //py:unit ``` To run tests with a specific browser: ```sh bazel test //py:test- ``` To run all Python tests: ```shell bazel test //py:all ```


Click to see Ruby Test Commands Test targets: | Command | Description | | -------------------------------------------------------------------------------- | -------------------------------------------------- | | `bazel test //rb/...` | Run unit, all integration tests and lint | | `bazel test //rb:lint` | Run RuboCop linter | | `bazel test //rb/spec/...` | Run unit and integration tests for all browsers | | `bazel test //rb/spec/... --test_size_filters small` | Run unit tests | | `bazel test //rb/spec/unit/...` | Run unit tests | | `bazel test //rb/spec/... --test_size_filters large` | Run integration tests for all browsers | | `bazel test //rb/spec/integration/...` | Run integration tests for all browsers | | `bazel test //rb/spec/integration/... --test_tag_filters firefox` | Run integration tests for local Firefox only | | `bazel test //rb/spec/integration/... --test_tag_filters firefox-remote` | Run integration tests for remote Firefox only | | `bazel test //rb/spec/integration/... --test_tag_filters firefox,firefox-remote` | Run integration tests for local and remote Firefox | Ruby test targets have the same name as the spec file with _spec.rb removed, so you can run them individually. Integration tests targets also have a browser and remote suffix to control which browser to pick and whether to use Grid. | Test file | Test target | | ------------------------------------------------------- | ---------------------------------------------------------------- | | rb/spec/unit/selenium/webdriver/proxy_spec.rb | //rb/spec/unit/selenium/webdriver:proxy | | rb/spec/integration/selenium/webdriver/driver_spec.rb | //rb/spec/integration/selenium/webdriver:driver-chrome | | rb/spec/integration/selenium/webdriver/driver_spec.rb | //rb/spec/integration/selenium/webdriver:driver-chrome-remote | | rb/spec/integration/selenium/webdriver/driver_spec.rb | //rb/spec/integration/selenium/webdriver:driver-firefox | | rb/spec/integration/selenium/webdriver/driver_spec.rb | //rb/spec/integration/selenium/webdriver:driver-firefox-remote | Supported browsers: * chrome * edge * firefox * firefox-beta * ie * safari * safari-preview In addition to the [Common Options Examples](#common-options-examples), here are some additional Ruby specific ones: * `--test_arg "-eTimeouts"` - test only specs which name include "Timeouts" * `--test_arg ""` - pass any extra RSpec arguments (see `bazel run @bundle//bin:rspec -- --help`) Supported environment variables for use with --test_env: - WD_SPEC_DRIVER - the driver to test; either the browser name or 'remote' (gets set by Bazel) - WD_REMOTE_BROWSER - when WD_SPEC_DRIVER is `remote`; the name of the browser to test (gets set by Bazel) - WD_REMOTE_URL - URL of an already running server to use for remote tests - DOWNLOAD_SERVER - when WD_REMOTE_URL not set; whether to download and use most recently released server version for remote tests - DEBUG - turns on verbose debugging - HEADLESS - for chrome, edge and firefox; runs tests in headless mode - DISABLE_BUILD_CHECK - for chrome and edge; whether to ignore driver and browser version mismatches (allows testing Canary builds) - CHROME_BINARY - path to test specific Chrome browser - CHROMEDRIVER_BINARY - path to test specific ChromeDriver - EDGE_BINARY - path to test specific Edge browser - MSEDGEDRIVER_BINARY - path to test specific msedgedriver - FIREFOX_BINARY - path to test specific Firefox browser - GECKODRIVER_BINARY - path to test specific GeckoDriver To run with a specific version of Ruby you can change the version in rb/.ruby-version or from command line: ```sh echo '' > rb/.ruby-version ```


Click to see .NET Test Commands .NET tests currently only work with pinned browsers, so make sure to include that. Run all tests with: ```sh bazel test //dotnet/test/common:AllTests --pin_browsers=true ``` You can run specific tests by specifying the class name: ```shell bazel test //dotnet/test/common:ElementFindingTest --pin_browsers=true ``` If the module supports multiple browsers: ```shell bazel test //dotnet/test/common:ElementFindingTest-edge --pin_browsers=true ```


Click to see Rust Test Commands Rust tests are run with: ```shell bazel test //rust/... ```


Click to see Linux Testing Requirements By default, Bazel runs these tests in your current X-server UI. If you prefer, you can alternatively run them in a virtual or nested X-server. 1. Run the X server `Xvfb :99` or `Xnest :99` 2. Run a window manager, for example, `DISPLAY=:99 jwm` 3. Run the tests you are interested in: ```sh bazel test --test_env=DISPLAY=:99 //java/... --test_tag_filters=chrome ``` An easy way to run tests in a virtual X-server is to use Bazel's --run_under functionality: ``` bazel test --run_under="xvfb-run -a" //java/... ```


API documentation can be found here:

To update API documentation for a specific language: ./go <language>:docs

To update all documentation: ./go all:docs

Note that JavaScript generation is currently broken.


The full process for doing a release can be found in the wiki

Releasing is a combination of building and publishing, which often requires coordination of multiple executions and additional processing. As discussed in the Building section, we use Rake tasks with the ./go command for these things. These ./go commands include the --stamp argument to provide necessary information about the constructed asset.

You can build and release everything with:

./go all:release

To build and release a specific language:

./go <language>:release

If you have access to the Selenium EngFlow repository, you can have the assets built remotely and downloaded locally using:

./go all:release['--config', 'release']