How to test in WebWorker? has some demo?

I want to test my javascript code for WebWorker compatibility.
In worker :
```javascript
importScripts("/lib/mocha.js", "/lib/should.js");
mocha.setup("bdd");
describe("test in webworker", () => {
it("get", async () => {
self.addEventListener.should.be.ok();
});
});
```

but this test case do not show in terminal or report.

I try [karma-mocha-webworker](https://www.npmjs.com/package/karma-mocha-webworker), also dont work.
Thank you for your reply.