Switch to web-test-runner test suite (#73)

This switches out Jest for web-test-runner, which is the test suite that
is recommended for web component building, especially from Lit:
https://lit.dev/docs/tools/testing/

This replaces manual DOM testing manipulation and instead tests inside
the browser environment instead. This is handy for picking up on
exceptions that wouldn't be caught outside the browser -- I picked up on
a couple just adding notification tests.

The Lit starter kit has some more examples of tests:

https://github.com/lit/lit-element-starter-js/blob/main/test/my-element_test.js

I just added some to test the functionality. This still requires some
mocking, as all imports do need to be JS modules -- CSS and JSON
included in that.

I've wanted to test this for the dashboard, but my environment was
broken all
day today, so I started testing here instead. We don't have any tests
written
yet anyways, so this is an easier place to start already, not to mention
the
footprint is smaller.

Author: agjohnson

.circleci/config.yml

@@ -1,9 +1,14 @@
 version: 2.1
 
+orbs:
+  browser-tools: circleci/[email protected]
+
 commands:
   run-tests:
     description: "Run test suite"
     steps:
+      - browser-tools/install-chrome
+      - browser-tools/install-chromedriver
       - checkout
       - run: npm ci
       - run: npm run test
@@ -37,7 +42,7 @@ jobs:
       - run-checks: {}
   test:
     docker:
-      - image: "cimg/node:18.15.0"
+      - image: "cimg/node:18.15.0-browsers"
     steps:
       - run-tests: {}
   build:
@@ -52,5 +57,4 @@ workflows:
     jobs:
       - checks
       - build
-  # TODO re-enable the test suite checks as CI later.
-  #    - test
+      - test

README.md

@@ -70,6 +70,7 @@ Display a nice tooltip when hovering internal links of the same documentation.
 - Make sure you have the correct version of Node.js installed (>= 18). You can use [asdf](https://github.com/asdf-vm/asdf) or [nvm](https://github.com/nvm-sh/nvm) for easier management of different Node.js versions.
 - Run `npm install` to install dependencies
 - Run `npm run dev` to start the local dev server. While this can run without a local Read the Docs development instance, not everything will work.
+- Run `npm test` to run the test suite, using web-test-runner. You can run also `npm run test:dev` to leave tests running in watch mode or `npm run test:debug` to manually test the suite in a browser.
 
 ----