Intern is written in TypeScript. The various build lifecycle steps (build, test, etc.) are handled through npm, and are mostly implemented by scripts in the intern-dev package.
The source is formatted using prettier 1.6+ and a .prettierrc file in the repo. This isn't automatic yet, so updates should be run through prettier manually (prettier src/changed_file.ts --write) or using an editor plugin.
Prettier doesn't (yet) reflow comments; those should be wrapped at 80 characters. Long lines for URLs are fine.
Before you can do much else, you'll need to install Intern’s development dependencies:
$ npm install
To build Intern, just run:
$ npm run build
To run the existing unit tests in Node, use:
$ npm test
To run unit tests in Node and a local instance of Chrome, use:
$ npm test config=@wd
Intern’s self tests work by using two different builds of the current version of Intern, one in _tests and one in _build. Both instances are generated when building Intern. The version in _tests is then used to run tests against the version in _build.
Tests are in the tests directory, and the test config is the intern.json file in the project root. Tests are organized by type in unit, functional, and benchmark directories. The directory structure within each type should mirror the main src directory structure. For example, unit tests for src/lib/executors/Executor should go in tests/unit/lib/executors/Executor.
As with the main Intern source, self-tests are written in TypeScript. The tests have their own tsconfig.json file that inherits from the main Intern tsconfig. The key difference is that the test tsconfig file defines a path mapping for the non-relative “src” path. This saves a bit of typing during test writing, but the main advantage is that this path can be re-mapped at runtime to point to files in the _build/src directory.
Self tests in the browser use the Dojo loader so that individual modules can be loaded in the browser, and to allow module dependencies to be mocked. The self-tests use the built-in dojo2 loader script.