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updated the testing page(s) added a new example.
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‎source/exercises/unit_testing/sum_13.py‎

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"""
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Test driven development:
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Example from Coding Bat: List-2 > sum13
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https://codingbat.com/prob/p167025
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Return the sum of the numbers in the array, returning 0 for an empty array. Except the number 13 is very unlucky, so it does not count and numbers that come immediately after a 13 also do not count.
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sum13([1, 2, 2, 1]) → 6
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sum13([1, 1]) → 2
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sum13([1, 2, 2, 1, 13]) → 6
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sum13([1, 2, 2, 1]) → 6
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sum13([1, 1]) → 2
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sum13([1, 2, 2, 1, 13]) → 6
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sum13([1, 2, 13, 2, 1, 13]) → 4
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sum13([13, 1, 2, 13, 2, 1, 13]) → 3
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sum13([]) → 0
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sum13([13]) → 0
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sum13([13, 13]) → 0
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sum13([13, 0, 13]) → 0
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sum13([13, 1, 13]) → 0
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sum13([5, 7, 2]) → 14
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sum13([5, 13, 2]) → 5
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sum13([0]) → 0
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sum13([13, 0]) → 0
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"""
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import pytest
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def sum13(nums):
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"""
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non-functional -- but the tests will run (and fail)
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"""
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return None
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# def sum13(nums):
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# """
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# simple sum -- no special handling of 13 -- should pass some tests.
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# """
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# return sum(nums)
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# def sum13(nums):
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# """
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# using a comprehension to filter out the 13s
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# - more tests should pass, but not all.
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# """
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# return sum(n for n in nums if n!=13)
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# def sum13(nums):
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# """
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# darn -- comprehension can't handle the "after a 13" case
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# do it from scratch with while loop
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# fails the two 13s in a row test!
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# """
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# total = 0
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# i = 0
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# while i < len(nums):
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# if nums[i] != 13:
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# total += nums[i]
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# else:
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# i += 1
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# i += 1
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# return total
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# def sum13(nums):
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# """
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# Use a for loop, and keep track of the previous 13
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# passes all tests!
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# """
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# print(nums)
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# total = 0
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# prev_13 = False
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# for i, n in enumerate(nums):
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# if n == 13:
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# prev_13 = True
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# continue
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# elif prev_13:
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# prev_13 = False
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# continue
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# else:
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# total += n
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# return total
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# def sum13(nums):
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# """
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# Use the iterator protocol -- nifty? but not any simpler really.
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# Fails for repeated 13 in middle
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# Works with any iterable, so that's nice.
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# """
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# total = 0
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# nums_i = iter(nums)
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# for n in nums_i:
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# if n != 13:
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# total += n
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# else:
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# try:
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# next(nums_i)
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# # this is necessary for the case where there's a 13 at the end.
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# except StopIteration:
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# break
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# return total

‎source/exercises/unit_testing/test_sum_13.py‎

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"""
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Test driven development:
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Example from Coding Bat: List-2 > sum13
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https://codingbat.com/prob/p167025
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Return the sum of the numbers in the array, returning 0 for an empty array. Except the number 13 is very unlucky, so it does not count and numbers that come immediately after a 13 also do not count.
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The tests that are used on codingbat:
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sum13([1, 2, 2, 1]) → 6
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sum13([1, 1]) → 2
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sum13([1, 2, 2, 1, 13]) → 6
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sum13([1, 2, 2, 1]) → 6
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sum13([1, 1]) → 2
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sum13([1, 2, 2, 1, 13]) → 6
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sum13([1, 2, 13, 2, 1, 13]) → 4
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sum13([13, 1, 2, 13, 2, 1, 13]) → 3
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sum13([]) → 0
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sum13([13]) → 0
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sum13([13, 13]) → 0
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sum13([13, 0, 13]) → 0
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sum13([13, 1, 13]) → 0
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sum13([5, 7, 2]) → 14
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sum13([5, 13, 2]) → 5
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sum13([0]) → 0
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sum13([13, 0]) → 0
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"""
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import pytest
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from sum_13 import sum13
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# Using the nifty pytest.parametrize, so we only have to write one test
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test_data = [
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([1, 2, 2, 1], 6),
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([1, 1], 2),
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([1, 2, 2, 1, 13], 6),
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([1, 2, 2, 1], 6),
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([1, 1], 2),
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([1, 2, 2, 1, 13], 6),
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([1, 2, 13, 2, 1, 13], 4),
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([13, 1, 2, 13, 2, 1, 13], 3),
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([], 0),
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([13], 0),
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([13, 13], 0),
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([13, 0, 13], 0),
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([13, 1, 13], 0),
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([5, 7, 2], 14),
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([5, 13, 2], 5),
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([0], 0),
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([13, 0], 0),
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# These are not part of original test suite
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# uncomment them, and see if your solution still passes.
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# ([3, 13, 13, 2, 5], 8),
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# (iter([13, 1, 2, 13, 2, 1, 13]), 3), # Does it work with an iterable?
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]
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@pytest.mark.parametrize('nums, result', test_data)
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def test_sum13(nums, result):
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assert sum13(nums) == result
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‎source/exercises/unit_testing/unit_testing.rst‎

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When the tests pass -- you are done! That's the beauty of test-driven development.
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Another Example:
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----------------
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Here's another example from the codingbat site:
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:download:`test_sum_13.py <test_sum_13.py>`
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Doing your own:
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---------------
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‎source/index.rst‎

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Programming in Python
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#####################
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This site holds many of the materials for the
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This site holds a set of materials for an introductory course in Python.
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THe course was originally developed by a wide variety of instructors for the
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`University of Washington Professional and Continuing Education Python Certificate <https://www.pce.uw.edu/certificates/python-programming>`_
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`Introductory class <https://www.pce.uw.edu/courses/programming-in-python>`_
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This site can be thought of as the textbook for Programming in Python: the first course in the program. It contains notes about the topics covered in the classes, programming exercises, supplemental materials about setting up a development environment, and assorted references about Python-related topics.
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This site can be thought of as the textbook for an introduction to programming in Python:
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It contains notes about the topics covered in the classes, programming exercises, supplemental materials about setting up a development environment, and assorted references about Python-related topics.
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Many of these topics can be useful on their own, but each assumes that you know concepts that were introduced earlier in the program, so working through them in order can be helpful.
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It is managed in this gitHub repository:
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https://github.com/UWPCE-PythonCert/ProgrammingInPython
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https://github.com/PythonCHB/ProgrammingInPython
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Readers are encouraged to report omissions, typos, or make suggestions for improvements via issues and pull requests on that repository.
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Assorted Example code can be found in the source repository for these documents. Most of the examples are linked to directly from these documents, but it might be helpful to have them all in one place:
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https://github.com/PythonCHB/ProgrammingInPython/tree/main/source/examples
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.. Indices and tables

‎source/modules/TestDrivenDevelopment.rst‎

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.. _test_driven_development:
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FIXME: change the path from my personal to something generic
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#######################
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Test Driven Development
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#######################
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"Test Driven Development" (TDD) is a development strategy that integrates the development of unit tests with the code itself. In particular, you write the tests *before* you write the code, which seems pretty backward, but it has some real strengths.
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We'll demonstrate this technique with an example.
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The following is adapted from Mark Pilgrim's excellent "Dive into Python":
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https://diveintopython3.problemsolving.io/
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This is called *test-driven development*, or TDD. The set of two
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conversion functions — ``to_roman()``, and later ``from_roman()`` — can
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conversion functions — ``to_roman()``, and later ``from_roman()`` — can
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be written and tested as a unit, separate from any larger program that
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Once installed, you should have the pytest command available in your terminal.
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Once installed, you should have the pytest command available in your terminal.
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Unit testing is an important part of an overall testing-centric
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.. note:: This is a major challenge of unit testing -- how to catch all the edge cases, without over testing every little thing.
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`pytest` makes it really simple to write a test case: simply define a function named ``test_anything``. pytest will identify any function with: "``test_``"" at the start of the name as a test function.
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`pytest` makes it really simple to write a test case: simply define a function named ``test_anything``. pytest will identify any function with: "``test_``" at the start of the name as a test function.
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* Every individual test is its own function. A test function takes no parameters, returns no value, and must have a name beginning with the five letters ``test_``.
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If a test function exits normally without a failing assertion or other exception, the test is considered passed; if the function raises a failed assertion, failed.
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That’s definitely *not* what you wanted — that’s not even a valid Roman
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That’s definitely *not* what you wanted — that’s not even a valid Roman
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numeral!
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In fact, after 3000, each of these numbers is outside the range of
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acceptable input, but the function returns a bogus value anyway.
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Of course, the ``to_roman()`` function isn’t raising the ``ValueError`` because you haven’t told it to do that yet.
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That’s excellent news! It means this is a valid test case — it fails before you write the code to make it pass.
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That’s excellent news! It means this is a valid test case — it fails before you write the code to make it pass.
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Now you can write the code to make this test pass.
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