Testing Python standard library and learning through play approach
Table of Contents
Preamble
In most cases the best approach to study how something works is to test its behavior in various circumstances. In a helicopter view it is a dissection or a scrutiny.
The same approach for studying programming language has a plethora benefits and the most significant is that it take you chance to play with code. Of cause studying by playing is a most natural way of learning.
Methodology
Template
Lets create a mold for pouring by the test suits:
#+BEGIN_SRC python :noweb yes :results none :tangle tests/test_built-in_constants.py """Discover how it works by a coherent testing""" <<import-header>> <<built-in-constants-test>> # it might be several test cases # thus several test classes # as several include source code block #+END_SRC
Tip Use
C-c C-v tto generate (tangle) the test file
Necessary imports
It's clear what you expected to test by means the unittest module:
#+NAME: import-header #+BEGIN_SRC python import unittest #+END_SRC
Test suits
Each test case class as a separate source code block with a particular name for substitution into template.
#+NAME: built-in-constants-test #+BEGIN_SRC python class TestBuiltInConstants(unittest.TestCase): def test_true(self): self.assertTrue(1 + 3 == 4) def test_false(self): self.assertFalse(1 + 4 == 4) def test_none(self): value = None self.assertIsNone(value) #+END_SRC
Obviously that arbitrary number of named blocks can exist there.
Test runner
Accustomed unittest as Python module:
#+BEGIN_SRC sh :results output :exports both python -m unittest -v tests/test_built-in_constants.py #+END_SRC #+RESULTS: : test_false (tests.test_built-in_constants.TestBuiltInConstants) ... ok : test_none (tests.test_built-in_constants.TestBuiltInConstants) ... ok : test_true (tests.test_built-in_constants.TestBuiltInConstants) ... ok : : ---------------------------------------------------------------------- : Ran 3 tests in 0.002s : : OK
Conclusion
Now it is totally clear how to compose tests for Python standard library testing in a literate programming style.
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