Python Weather CLI

Requirements

This project has two sets of requirements:

• Minimum requirements: Only what you need to run the app.
• Optional (development) requirements: For testing, code formatting, and linting. Recommended if you want to contribute or check code quality.

Minimum requirements

• Python 3.10 or later
• requests
• python-dotenv

Install with:

pip install -r requirements.txt

Optional (development) requirements

• pytest: Run tests
• pytest-mock: Mocking for tests
• pytest-cov: Test coverage reporting
• black: Code formatter (auto-formats Python code)
• flake8: Linter (checks code style and errors)
• mypy: Type checker (checks type hints)
• types-requests: Type stubs for requests (for mypy type checking)

Install with:

pip install -r requirements-dev.txt

If you only install the minimum requirements, you can run the app but not run tests, lint, or format code.

What is this?

A simple Python command-line app that fetches and displays the current weather for any city using the OpenWeatherMap API. You run it from the terminal and get the city name, temperature (Celsius), and weather description.

Installation

1. Clone the repository

git clone <repository-url>
cd python-weather-cli

2. Set up your API key

This project uses a .env file for the API key. You must set your OpenWeatherMap API key in this file.

1. Sign up at OpenWeatherMap and get your API key.
2. Copy the example file and add your key:

cp .env.example .env
# Edit .env and set your key:
# OPENWEATHERMAP_API_KEY=your_api_key_here

3. Set up virtual environment (recommended)

python3 -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

4. Install the package

Recommended: Editable installation with dev tools

This installs the package in "editable" mode, so code changes are immediately reflected:

pip install -e .
pip install -r requirements-dev.txt

Fallback: Basic installation (no dev tools)

pip install .

Usage

Run the app from the project root:

python -m weather_cli.main "London"
python -m weather_cli.main "New York"
python -m weather_cli.main "Tokyo"

Or use the installed script:

weather "London"
weather "New York"  
weather "Tokyo"

You can use any city name. The app will print the current weather for that city.

Command-line help

You can see all available options with:

python -m weather_cli.main --help

Or:

weather --help

Example output:

usage: weather-cli [-h] [--debug] city

Get current weather information for a city

positional arguments:
  city        Name of the city to get weather for

options:
  -h, --help  show this help message and exit
  --debug     Enable debug logging

Project Structure

python-weather-cli/
├── .env.example
├── README.md
├── requirements.txt
├── requirements-dev.txt
├── setup.py
├── pyproject.toml
├── src/
│   └── weather_cli/
│       ├── __init__.py
│       ├── main.py
│       ├── weather_service.py
│       ├── weather_client.py
│       ├── weather_data.py
│       ├── config_util.py
│       └── exceptions.py
├── tests/
└── docs/

Development commands

Important: Activate the virtual environment first if you created one:

source venv/bin/activate

• Run all tests:

  pytest

• Run tests with coverage:

  pytest --cov=weather_cli tests/

• Format code with black:

  black src tests

• Lint code with flake8:

  flake8 src tests

• Type check with mypy:

  mypy src

Testing

This project includes comprehensive unit tests covering all major components and functionality. The test suite ensures reliability, security, and proper error handling across the application.

Quick testing commands (remember to activate venv first: source venv/bin/activate):

• Run all tests: pytest
• Run with coverage: pytest --cov=weather_cli tests/
• Run specific test file: pytest tests/test_weather_client.py

The testing approach includes:

• Unit testing with mocked dependencies for isolation
• Error handling testing for all failure scenarios
• Security testing to ensure API keys aren't exposed
• Input validation testing for edge cases and malicious input
• Integration testing of component interactions

For detailed information about what is tested and how, see tests/TESTING.md.

Code style

• This project uses black for formatting and flake8 for linting.
• The maximum line length is set to 100 characters for both tools.
• Target Python version: 3.10+

To check code style:

flake8 src tests

To auto-format code:

black src tests

To type check:

mypy src

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For more details, see the code and comments in each file.