The Scenario
A teammate wrote a `formatRelativeDate(dateString)` function that returns "just now", "5 minutes ago", "yesterday", etc. However, it sometimes breaks on leap years and cross-timezone inputs. You need to write the tests to prove it.
The Brief
Write a comprehensive Jest or Mocha test suite for the `formatRelativeDate` function. Focus on testing the edge cases (leap years, different timezones, invalid inputs) rather than just the happy path.
Deliverables
- The complete test suite code (e.g., `dateFormatter.test.js`)
- A short explanation of why it is important to mock the system clock (`Date.now()`) when testing time-relative functions
Submission Guidance
Assume the function exists and you are just writing the tests. A good test suite should act as documentation for the function’s expected behavior.
Submit Your Work
Your submission is graded against the rubric on the right. If you pass, you get a public Badge URL you can share on LinkedIn. There is no draft save, so work offline first and paste your finished response here.