TDD Outside-in, London-School TDD, Discovery-Testing and Code Kata

- [A code kata about London-School approach](https://github.com/testdouble/contributing-tests/wiki/Unusual-Spending-Kata)
- [What is the London-School TDD](https://github.com/testdouble/contributing-tests/wiki/London-school-TDD)
- [What Discovery-Testing means?](https://github.com/testdouble/contributing-tests/wiki/Discovery-Testing)