This is basically a full debugging exercise compressed into one prompt.
Start by reproducing the failures and reading the test output carefully to understand what's expected versus actual. Then systematically trace each failure to its root cause using debugging tools, fix the bugs with minimal changes, and add regression tests that would have caught each bug. Finally, explain your debugging strategy and tooling choices, emphasizing how you balance speed with thoroughness.
Pro tip: Before diving into fixes, quickly scan the codebase for patterns—often multiple failures share a common root cause, and fixing that one issue resolves several tests. Also, articulate your hypotheses out loud as you debug; it demonstrates structured thinking and makes your process easy to follow.
Run the test suite to see all failures, then read the test code and error messages to understand what each test expects and why it's failing. Group failures by likely common causes.
For each failure group, use debugging tools (e.g., debugger, logging, breakpoints) to trace the execution path and identify the exact line(s) causing incorrect behavior. Form hypotheses and verify them.
Apply the smallest possible fix that addresses the root cause without introducing side effects. Re-run tests to confirm the fix resolves the failures and doesn't break other tests.
Add focused unit tests that specifically target the fixed bugs, ensuring they would fail if the bug were reintroduced. Keep tests minimal and clear.
Summarize your debugging approach, the tools you used (e.g., debugger, logging, test runners), and how you balanced speed with thoroughness. Highlight any trade-offs made.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.