Software development practices in python

Software development practices in python

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  Software Development Practices in Python Jimmy Lai r97922028 [at] ntu.edu.tw http://tw.linkedin.com/pub/jimmy-lai/27/4a/536 2013/02/14
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  Outline 1. Runtime Environment:virtualenv and pip 2. Source Code Management: – Version control: Mercurial – Unit test: code coverage • doctest • nosetests – Coding convention: PEP8 – Code duplication: clonedigger 3. Documentation: Sphinx 4. Automation: fabric Software Development Practice in Python 2
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  Demo Code $ hgclone https://bitbucket.org/noahsark/slideshare Demo Codes are in python_demo dir. Files: 1. my_operator.py, my_operator_test.py 2. fabfile.py Software Development Practice in Python 3
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  Runtime Environment -virtualenv • Isolates runtime environment dependency of your python project. $ virtualenv --no-site-packages env_name $ . env_name/bin/activate # enter the virtual environment $ pip install package_name # install python packages Software Development Practice in Python 4
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  Source Code Management Version Control - Mercurial • Distributed repositories Ignore some files shown in • Common commands: `hg status` $ hg clone File: .hgignore ssh://hg@bitbucket.org/noahs syntax: glob ark/slideshare $ hg commit *.pyc *.swp $ hg push docs/build $ hg fetch • Useful hooks: http://pypi.python.org/pypi/hghooks/ Software Development Practice in Python 5
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  Source Code Management Unit Test - nose • nose def setup(): global test_case_1 – Simpler and easier than test_case_1 = (1, 2) unittest def teardown(): – Nose tests in XXX_test.py pass and functions named test_XXX def adder(a, b): return a + b $ pip install nose @with_setup(setup, teardown) # install def test_adder(): $ nosetests expected = 3 actual = adder(test_case_1[0], # nose tests and execute test_case_1[1]) nt.assert_equal(actual, expected) Software Development Practice in Python 6
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  Source Code Management Unit Test - doctest • Doctest def adder(a, b): ''' – Write test in the >>> adder(2, 3) docstring of function 5 – Easy and simple ''' return a + b – The test case is a usage example and appears in documents. • http://docs.python.org/ 2/library/doctest.html Software Development Practice in Python 7
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  Source Code Management Unit Test – Test Coverage • Test is the shield of Name Stmts Miss Cover Missing ------------------------------------------------------- code. Test coverage is python_demo 0 0 100% the percentage of code python_demo.fabfile 23 15 35% 13-14 be covered by test cases. python_demo.my_operator 6 0 100% ------------------------------------------------------- • Coverage rate over 80% TOTAL 29 15 48% is good. $ pip install coverage $ nosetests --with-coverage # run coverage by nose Software Development Practice in Python 8
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  Source Code Management Coding Convention – PEP8 • http://www.python.org/dev/peps/pep-0008/ • Code layout consistency: – Usage of indentation, space, blank line – Naming convention – Programming recommendations • Setup PEP8 checking as mercurial hook to ensure the consistency. pretxncommit.pep8 = python:hghooks.code.pep8hook Software Development Practice in Python 9
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  Source Code Management Code Duplication - clonedigger • Duplicated codes should be refactored as reusable module $ pip install clonedigger $ clonedigger . Output example $ firefox output.html Software Development Practice in Python 10
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  Documentation - Sphinx •Document is important for reuse • Document type: – Tutorial, system architecture – Functions, modules explanation • Sphinx: write docs in reStructuredText $ pip install sphinx Refer to http://www.slideshare.net/jimmy_lai/documentation-with-sphinx for more detail. Software Development Practice in Python 11
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  Automation - fabric •Automation reduces • Common tasks suitable repeating efforts. for automation: • Things you do for the – Build executable second time is worth to – Build document (fab doc) automate. – Run unit tests (fab test) $ pip install fabric – Setup Runtime Environment (fab setup) – Deploy • See fabfile.py for more examples. Software Development Practice in Python 12