# Web Serial Testing 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. [MojoJS]: https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/testing/web_platform_tests.md#mojojs [WebUSB]: ../webusb [Web Serial API]: https://wicg.github.io/serial