Unit Testing: doctest and unittest (PyUnit)

Test-driven development Instead of putting off testing until the end, Write your test cases before you code!● Once you have the design/specification(e.g., pre/post-conditions of a method),● Write comprehensive test cases first● Then code and test along the way● Your code is correct if it passes all the tests Unit testing: each class/method in isolation Integration testing:do all components work correctly together?CMPT140: unit testing 30 Nov 20106

Test frameworks in Python Python has two built-in libraries to help you withrunning tests (plus more 3rd-party libraries): doctest: simple framework, easy to use● “Test script” goes in docstring● Small function at bottom of file runs tests unittest (PyUnit): more sophisticated● Test cases organized into test suites● Test cases may share common test fixturesCMPT140: unit testing 30 Nov 20107

doctest: simple test library In each docstring, include a test script:“””Calculate factorial.>>> factorial(5)24“”” Command/response exactly as in IDLE:● Prefix commands with '>>>'● Put expected output on line by itself● If you expect an exception, write theexpected “red text” for the exception! More details in Python doctest library docsSee factorialtest.pyCMPT140: unit testing 30 Nov 20108

doctest: running tests To run doctest, put this function at the end:if __name__ == “__main__”:import doctestdoctest.testmod() The if statement prevents the tests from beingrun if another program is importing the module doctest.testmod() scans through all docstringsin the file and runs all test cases it can find If all tests succeed, output is silent If any tests fail, a report is output to screen You can also run: python -m doctest myfile.pyCMPT140: unit testing 30 Nov 20109

doctest: test narratives doctest searches your docstrings for textresembling a test script (e.g., '>>>') You can also put your test scripts in a separatefile, interspersed amongst your documentation● As though the whole file were a docstring A test narrative is a document written forhumans (e.g., user manual) where test casesare interleaved with the narrative See factorialtest.txt for an example Run: python -m doctest factorialtest.txt Or in code: doctest.testfile(“factorialtest.txt”)CMPT140: unit testing 30 Nov 201010

GOOD NEIGHBORS USANOTES TO FINANCIAL STATEMENTS (Continued)Income TaxesThe Organization is a nonprofit organization that is exempt from federal income tax underInternal Revenue Code Section 501(c)(3).NOTE C - PROPERTY AND EQUIPMENTProperty and equipment consisted of the following at December 31, 2009:Automobile $ 22,645Computer 3,254Office equipment and fixture 9,839Website 76,650Total property and equipment 112,388Less: Accumulated depreciation (28,684)Property and equipment, net $ 83,704Depreciation expense for the year ended December 31,2009 was $ 19,757.NOTE D - ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES:Accrued expenses and other current liabilities at December 31, 2009 consist of the following:Accrued liabilities $ 517Contract payable,current 3,977Payroll taxes 4,433NOTE E — Contract Payable$ 8,927Contract payable on automobile, 11.49% note, interest and principal due monthly, is $7,710 atDecember 31, 2009, and scheduled debt maturity for future years ending December 31 are asfollows:2010 $ 3,9772011 3,733• 9

unittest: running tests Put the following at the end of the file of tests:if __name__ == '__main__':unittest.main() Run from the command line:python myunittests.py Outputs results and any failures Can also run from IDLE, but it will try toSystemExit after tests are finishedCMPT140: unit testing 30 Nov 201013