Testing

Servo has a test suite which runs on every reviewed pull request, via bors-servo and the buildbot. It uses Mozilla's Mach system to run the tests.

You can run the test suite yourself through these ./mach commands:

• ./mach test-unit: Runs unit tests (functions tagged with #[test]) inside Servo and its dependencies. May also run ref or content tests depending on your platform.
• ./mach test-wpt: Runs the web platform tests on Servo.
• ./mach test-scripts: Run tests for Servo's python support scripts.
• ./mach test-tidy: Run lints against your local changes.

Writing test

• Write wpt/css tests
• Write unit tests: these are common Rust programs under tests/unit, and are organized to reflect the components tree. You can follow the existing structure and Rust testing guide

Assign a Temporary Hostfile for Testing

In some tests (e.g. wpt tests), you need to use a hostfile to translate testing domain names to real IPs. For example, translating wpt1.testserver.com to 127.0.0.1. But you may not have the permission to change the system hostfile in a shared server. Instead, you can assign a temporary hostfile using the HOST_FILE environment variable.

First, create a hostfile, say /tmp/hostfile.txt, in the following format ip<single space>hostname<new line>. For example:

127.0.0.1 wpt1.testserver.com
127.0.0.1 wpt2.testserver.com

Then, set the HOST_FILE environment variable as the absolute path to the hostfile.

export HOST_FILE=/tmp/hostfile.txt

Now, if you open http://wpt1.testserver.com in servo, you will go to http://127.0.0.1 directly.