Write tests that fail

The assistant wrote the code and the tests, and everything is green. Your job: write the test that should have failed. Happy paths, tautologies, missing boundaries and over-mocking.

2 exercises · ~13 min · 9 more coming soon

What you will practice

• Find the boundary and empty inputs a test suite never tried
• Spot tests that recompute the bug instead of checking the contract
• Write a failing test before you write the fix

1. 1.

   The age validator that only tested the happy path

   Tests · TS · 5 min

2. 2.

   Shipping tests that only confirm the code

   Tests · TS · 8 min