Lesson 15 — Debugging code you did not write
Unit II · Computational problem solving

L15_check.py                                 student     The L14 test helper under the L15 name.
L15_example_late.py                          student     Worked example: minutes_late with a fault, its tests and evidence prints.
L15_demo_function.py                         student     Walkthrough 1: pass_rate with a boundary logic bug.
L15_demo_tests.py                            student     Tests that expose the walkthrough 1 bug.
L15_demo_broken.py                           student     Walkthrough 2: program that raises TypeError (text added to a number).
L15_rest_check.py                            student     The L14 fallback function, unchanged, for diagnosis.
L15_diagnosis_log.txt                        student     Diagnosis log template: test, hypothesis, evidence, change, re-test, AI-use record.

Python 3.11 or newer. Standard library only. Run each program from the folder the lesson tells you to put it in:
    python <file>.py        (Windows)
    python3 <file>.py       (macOS and Linux)
