Automated testing for the Web Serial API relies on a test-only interface which must be provided by browsers under test. This is similar to WebUSB however there is no separate specification of the API other than the tests themselves and the Chromium implementation.
Tests in this suite include resources/automation.js to detect and load the test API as needed.
The Chromium implementation is provided by ../resources/chromium/fake-serial.js using MojoJS.
Tests with the “-manual” suffix do not use the test-only interface and expect a real hardware device to be connected. The specific characteristics of the device are described in each test.