Python style guide

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Coding style and best practices for writing Python code for Software Heritage.

General rules

  • As a general rule, follow the Google Python Style Guide.
  • Target Python 3. Do not care about backward compatibility with Python 2.

Specific rules

As supplement/overrides to the above general rules, follow the additional recommendations below.

Lint

  • Make sure your code is flake8 clean.

Tests

  • use unittest for assertions, nosetests3 as test runner
  • put tests/ dir down deep in the module hierarchy, near to the code being tested
  • naming conventions:
    • tests/test_mymodule.py
    • class TestMyEntity(unittest.TestCase)
    • def behavior(self):
      • do not prepend test_ to all test methods; use nose's @istest decorator instead

Classes

Strings

  • Prefer 'single quotes' over "double quotes". Do otherwise only when needed, e.g., for strings that should contain single quotes

Docstrings

See also