I’m attempting to use the lit testing dependencies in a pure TypeScript project.

So I’ve installed the dependencies like this:

npm i -D @open-wc/testing@latest
npm i -D @web/test-runner
npm i -D @web/test-runner-playwright
npm i -D @web/dev-server
npm i -D @web/dev-server-legacy

and downloaded all the Playwright browsers with:

npx playwright install  

The test I’m trying to run looks like this:

import { expect, fixture, html  } from "@open-wc/testing";
import { HelloWorldComponent } from "../hello-world.component";
describe("hello-world.component test", () => {
  it("works", async () => {
    const el: HTMLElement = (await fixture(
      html`<hello-world></hello-world> `
    )) as HelloWorldComponent;
    expect(el).not.to.equal(null);
  });
});

When I try to run this it with these test package.json scripts:

    "test": "npm run test:dev && npm run test:prod",
    "test:dev": "wtr",
    "test:watch": "wtr --watch",

These errors are produced:

 ???? Browser logs on Chromium:
      ReferenceError: describe is not defined
        at src/test/hello-world.component.spec.ts:3:0
 ???? Browser logs on Firefox:
      ReferenceError: describe is not defined
        at src/test/hello-world.component.spec.ts:3:0
 ???? Browser logs on Webkit:
      ReferenceError: Can't find variable: describe
        at module code (src/test/hello-world.component.spec.ts:3:9)

I’m guessing that Mocha needs to be installed as well, and perhaps lit pulls it in as a indirect dependency, because I don’t see it as a direct dependency. Does anyone have any insight?