The library has two sets of unit tests, one for the browser environment and another for the Node.js environment. The reason for this is that some SVG features cannot be easily tested in a Node.js (jsdom) environment.
Browser unit tests are done using Karma and QUnit. They can be launched with the following command:
npm run test:browser
Node.js unit tests are done using Jest, and can be launched with the following command:
npm test