What linting is

Linting is static analysis that flags issues like:

• unused imports/variables
• suspicious logic
• inconsistent style
• complexity / maintainability issues

Linting runs without executing your code.

Linting vs formatting vs type checking

• Linting: “this looks wrong / risky / inconsistent”
• Formatting: “make code look consistent” (e.g., Black)
• Type checking: “types don’t match” (e.g., Mypy)

Diagram: quality tools overview

  graph TD
A[Source code] --> B[Formatter\n(Black)]
A --> C[Linter\n(Pylint/Flake8)]
A --> D[Type checker\n(Mypy)]
A --> E[Security scan\n(Bandit)]
A --> F[Complexity\n(Radon)]

Why linting matters

• catches bugs before runtime
• keeps large codebases consistent
• makes PR reviews faster

🧪 Try It Yourself

Exercise 1 – Write a unittest TestCase

Exercise 2 – assertRaises

Exercise 3 – setUp and tearDown