Beyond 100% test coverage

A.K.A.

• Why 100% test coverage is not good enough
• Typing + Unit tests

About me and the demo

https://fluid.quest/pyconse2022

Problem statement

A CLI tool which

• Read a CSV file containing a list of cities and their founding year
• Does some operation, for example, printing the result

How does typing help you?

• Find edge cases such as type inconsistencies
• Sniff out issues with branches (if-else statements) and mutations in your code

Is typing a replacement for tests?

No! Typing will not ensure:

• Validation or correctness of your code
• Regressions won't happen in the future

A good test suite is still required to avoid such problems

Bonus

• pyupgrade: Let's you quickly transition to type hinting generics in Python 3.9+
• stubgen: CLI tool to generate

Thanks