Building geckodriver ==================== geckodriver is written in [Rust], a systems programming language from Mozilla. Crucially, it relies on the [webdriver crate] to provide the HTTPD and do most of the heavy lifting of marshalling the WebDriver protocol. geckodriver translates WebDriver [commands], [responses], and [errors] to the [Marionette protocol], and acts as a proxy between [WebDriver] and [Marionette]. To build geckodriver: % ./mach build testing/geckodriver If you use artifact builds you may build geckodriver using cargo, since mach in this case does not have a compile environment: % cd testing/geckodriver % cargo build … Compiling geckodriver v0.21.0 (file:///home/ato/src/gecko/testing/geckodriver) … Finished dev [optimized + debuginfo] target(s) in 7.83s Because all Rust code in central shares the same cargo workspace, the binary will be put in the `$(topsrcdir)/target` directory. You can run your freshly built geckodriver this way: % ./mach geckodriver -- --other --flags See for how to run tests. [Rust]: https://www.rust-lang.org/ [webdriver crate]: https://crates.io/crates/webdriver [commands]: https://docs.rs/webdriver/newest/webdriver/command/ [responses]: https://docs.rs/webdriver/newest/webdriver/response/ [errors]: https://docs.rs/webdriver/newest/webdriver/error/enum.ErrorStatus.html [Marionette protocol]: /testing/marionette/doc/marionette/Protocol.html [WebDriver]: https://w3c.github.io/webdriver/ [Marionette]: /testing/marionette/doc/marionette