COMP1531

3.3 - SDLC Testing - pylint

What is good style?

Programs must be written for people to read, and only incidentally for machines to execute — Abelson & Sussman, "Structure and Interpretation of Computer Programs"

Style

• Ultimately about readability and maintainability
• Style guides give rules of thumb and conventions to follow
• ...but good style is ultimately hard, if not impossible, to measure
• That said, tools can be a lot of help

There are a lot of tools in modern software engineering

Pylint

• An external tool for statically analysing python code
• Can detect errors, warn of potential errors, check against conventions, and give possible refactorings
• By default, it is very strict
• Can be configured to be more lenient

Controlling Messages

• Disable messages via the command line

    $ pylint --disable=<checks> <files_to_check>

    $ pylint --disable=missing-docstring <files>

• Disable messages in code; e.g.

    if year % 4 != 0: #pylint: disable=no-else-return

• Disable messages via a config file
  • If a .pylintrc file is in the current directory it will be used
  • Can generate one with:

    pylint <options> --generate-rcfile > .pylintrc