This directory contains utilities intended for use by tests and maintained as project infrastructure. It does not contain tests.
testharness.js is a framework for writing low-level tests of
browser functionality in javascript. It provides a convenient API for
making assertions and is intended to work for both simple synchronous
tests, and tests of asynchronous behaviour.
Complete documentation is available in the docs/ directory of this repository
and on the web at https://web-platform-tests.org/writing-tests/.