The failing tests covered stuff like adding a movie to a list, handling duplicates, deleting movies, bulk add then delete one by one, and then the edge cases where the list doesn't even exist.
Start by running the test suite to see the exact failures and error messages, then systematically trace each failure to its root cause in the code. Fix issues one by one, re-running tests after each change to confirm progress and avoid introducing new bugs. Finally, verify all tests pass and consider edge cases or code quality improvements.
Pro tip: Narrate your debugging process out loud, explaining your hypotheses and how you validate them. This demonstrates structured problem-solving and communication skills, which are highly valued at Amazon.
Run the test suite to see which tests fail and read the error messages and stack traces carefully. Identify the specific assertions or exceptions that indicate the problem.
For each failing test, trace the code path from the test to the implementation to pinpoint the root cause. Use debugging tools or add logging if needed to inspect variable states.
Make a targeted fix for one failure at a time, then re-run the relevant tests to confirm the fix works and doesn't break other tests. Repeat until all tests pass.
After all tests pass, review your changes for code quality, consistency, and potential edge cases. Consider if any fixes could be improved or if there are underlying design issues.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.