SPIKE: add testing functionality

Title

• Add new testing functionality, either unit tests, e2e tests, or both.

Description

• With any functionality added, there is a need to ensure that the functionality residing in the rest of the application works as expected.
• Unit tests are important to test individual components of code in isolation.
• E2E tests are important in testing a whole workflow from start to finish.

Current Behavior

• There are currently no tests or testing frameworks running.

Expected Behavior

• At least have one testing framework to ensure the validity of the app.
• It is also important when having huge PRs that affect multiple pages.

Environment

• Tests that work locally need to be updated to work in the CI environment.

Possible Solution

• E2E can be a first goto, for both the docs and the app.

Related Issues / PRs

• An example PR that needs heavy testing based on the number of changes.

Additional Context / Comments

• Any additional context can be provided via comments or Slack.

Docs for unit tests and E2E

Check Playwright too.