Java Engineer Builds Python Countdown Timer CLI to Master Time Control and Exception Handling

A Java developer documenting their journey learning Python from scratch has built a countdown timer command-line tool as the third project in their Python series. The tool lets users choose a countdown duration from a menu, ticking down one second at a time while overwriting the same terminal line using carriage return characters. The project focused on key Python concepts including time.sleep(), reverse loops with range(), and exception handling using try/except/finally blocks to manage interruptions like Ctrl+C. The developer also explored testing techniques such as mocking time.sleep to deliberately trigger exceptions and capturing standard output with pytest's capsys fixture. The article is part of an ongoing series where the author shares honest reflections on their learning process, clearly distinguishing between self-written code and AI-assisted guidance.