A Python collection of coding exercises based on the Dave Thomas CodeKata series, plus a standalone number-to-words converter. Each kata is one implementation module paired with a comprehensive test module.

The exercises range from algorithmic drills to design explorations. Several modules are runnable as small demos directly from the command line.

code_kata/
├── kata_1_supermarket_pricing.py
├── kata_2_karate_chop.py
├── ...
├── kata_17_more_business_rules.py
├── kata_18_transitive_dependencies.py
├── kata_19_word_chains.py
├── kata_20_klondike.py
├── kata_21_simple_lists.py
├── number_to_string_converter.py
├── test_kata_1_supermarket_pricing.py
├── ...
├── test_kata_21_simple_lists.py
├── test_number_to_string_converter.py
├── data/
│   ├── football.dat        ← used by kata 4
│   ├── weather.dat         ← used by kata 4
│   ├── wordlist.txt        ← used by katas 6 and 8
│   └── words.txt           ← used by kata 5
├── pyproject.toml
├── uv.lock
└── README.md

• Python 3.14+
• pytest (declared in pyproject.toml)

uv sync
source .venv/bin/activate

python3.14 -m venv .venv
source .venv/bin/activate
pip install -e .

Full suite:

python -m pytest -q

Single kata:

python -m pytest -q test_kata_14_trigrams.py

Single class or test by name:

python -m pytest -q test_kata_15_diversion.py::TestFibonacciRelationship
python -m pytest -q test_kata_2_karate_chop.py -k canonical

Most kata modules include a short runnable demo behind if __name__ == "__main__"::

python kata_1_supermarket_pricing.py
python kata_11_sorting_it_out.py
python kata_14_trigrams.py
python kata_15_diversion.py
python kata_16_business_rules.py
python kata_17_more_business_rules.py
python kata_18_transitive_dependencies.py
python kata_19_word_chains.py
python kata_20_klondike.py

• Each implementation module has a matching test_*.py file with comprehensive coverage including edge cases.
• The tests are the authoritative source of truth for intended behaviour.
• The test suite is the primary verification mechanism; demos are for quick manual inspection only.
• pyproject.toml declares only pytest as a dependency.
• main.py is a placeholder and is not the entry point for the project.

1. Read the implementation module's docstring to understand the design approach.
2. Read the corresponding test file to see the expected behaviour and edge cases.
3. Run the focused tests to confirm they pass before making changes.
4. Modify or extend the implementation, then re-run the full suite.

# Example: explore kata 20
python -m pytest -q test_kata_20_klondike.py
python kata_20_klondike.py