Python

Test Driven Development

• 100% unit test coverage (must)

• use pytest fixtures to mock/create dependencies, functional tests have the functional marker, integration are using a fixture called integration.

• Test driven development with functional/integration and unit test (should)

  concept: http://en.wikipedia.org/wiki/Test-driven_development

  1. write function/integration test
  2. write unit test (simplest statement first)
  3. switch between writing code and change/extend tests until all test pass
  4. refactor

Refactor towards Clean Code

see (Refactoring & Clean Code)

Imports

• one import per line
• don’t use * to import everything from a module
• don’t use relative import paths
• dont catch ImportError to detect wheter a package is available or not, as it might hide circular import errors. Instead use pkgresources.getdistribution and catch DistributionNotFound. (http://do3.cc/blog/2010/08/20/do-not-catch-import-errors,-use-pkg_resources/)

Code formatting

• 4 spaces instead of tabs (must)
• no trailing white space (must)
• pep8 (must)
• pyflakes (must)
• pylint (should)
• mcabe (should)
• Advances String Formatting pep3101 (must)
• Single Quotes for strings except for docstrings (must)

Docstring formatting

• pep257 (must, bei tests und zope.Interface classes should)

• python 3 type annotation (must) according to https://pypi.python.org/pypi/sphinx_typesafe

• javadoc-style parameter descriptions, see http://sphinx-doc.org/domains.html#info-field-lists (should)

• example:

  def methodx(self, a: dict, flag=False) -> str:
      """Do something.
  
      :param a: description for a
      :param flag: description for flag
      :return: something special
      :raise ValueError: if a is invalid
      """