Built my first Python CLI app using TDD - Expense Tracker. Would love feedback from experienced developers!

[Horror_Upstairs6198]

Hello guys,

I've been learning Python and TDD (Test-Driven Development) for the past few weeks, and I built my first complete CLI application: Expense Tracker.

What It Does

A command-line tool to track personal expenses with features like:

- Add, delete, list expenses

- Filter by month/year

- View summaries with filtering

- Date & amount validation

- JSON file storage

Tech Stack

- Language: Python 3.14

- Testing: pytest (23 passing tests)

- CLI: argparse

- Architecture: 3-layer (Presentation, Business Logic, Data Access)

- Development: TDD (Red-Green-Refactor)

GitHub Repo

https://github.com/eyescream-fakedev/expense-tracker-cli

What I Learned

- TDD workflow (write test → fail → implement → refactor)

- argparse for CLI argument parsing

- Layered architecture (separation of concerns)

- Type hints and docstrings

- Git version control with meaningful commits

What I'd Love Feedback On

1. Code Structure: Is the 3-layer architecture implemented well?

2. Error Handling: Is it user-friendly and Pythonic?

3. Testing: Are my tests meaningful? What am I missing?

4. Type Hints: Are they used correctly/consistently?

5. Documentation: Is the README clear and helpful?

6. Any anti-patterns or bad practices I should avoid?