Design test-run logging and query functions

##### Question Implement log(test_id, timestamp, status) to record a test run, where timestamps are strictly increasing across all test IDs. Implement get_min_time_to_pass(test_id) that returns the minimum time length for the specified test to change from failing to passing status, using the first failure in any consecutive failure series, or null if the test never passes. Implement log(test_id, timestamp, status) as above for a follow-up scenario. Implement get_longest_failure_window(min_tests) that returns {start_timestamp, end_timestamp} for the maximum contiguous period where at least min_tests tests are failing simultaneously; return null if no such window exists.