yFiles for HTML Jest Demo

Jest Demo

The Jest demo shows how to use Jest for unit testing a yFiles for HTML application.

To run the unit tests:

  1. Go to the demo's directory demos-js/testing/jest.
  2. Run npm install.
  3. Run the unit tests with npm run test.

yFiles and Jest

While modern JavaScript (or TypeScript) applications usually use JavaScript modules, Jest's support for native JavaScript modules is still experimental. For this reason, JavaScript modules code is transpiled. Due to its size, transpiling the yFiles JavaScript modules library is rather slow. As a workaround, it is possible to map the JavaScript modules variant of yFiles to its UMD variant, which does not need to be transpiled. This can be achieved with Jest's moduleNameMapper configuration option.

Some parts of yFiles require a complete DOM implementation, which Jest's JSDOM environment does not provide. To still be able to test code that uses yFiles API that require a DOM, it is necessary to mock yFiles. See the tests/ItemFactoryWithMock.test.js file for details.