Expert Python Programming - Third Edition

Test-Driven Development

Test-driven development (TDD) is a methodology that aims to produce high-quality software by concentrating on automated tests. It is widely used in the Python community, but it is also very popular in other communities.

Testing is especially important in Python due to its dynamic nature. Python lacks static typing, so many, even minute, errors won't be noticed until the code is run and each of its lines is executed. But the problem is not only how types in Python work. The most troublesome bugs are not related to bad syntax or wrong type usage, but rather to logical errors and subtle mistakes that may lead to major failures.

In order to efficiently test your software, you often need to use a wide variety of testing ...