{"id":"solution-test-colocation-convention","text":"Each problem directory contains a `solution.py` with both the `Solution` class and a `unittest.TestCase` subclass, runnable standalone via a `__main__` guard.","truth_value":"IN","source":"entries/2026/06/06/find-numbers-with-even-number-of-digits-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"solution-test-colocation-convention","truth_value":"IN","reason":"premise"}]}}