Python Test standard library doctest

Introduction:

Doctest is a standard library for testing in Python. This library is used to simulate console dialogs to detect correct values.

As the name implies, this module is looking for a part of the program inside a python interactive interpreter, and then running this section and comparing the results provided to determine whether the actual running results are consistent with the results you want.

Basic use: 1. Pass docstrings Test

Let's start by creating a example.py with the following code

1 " "2 Docstrings can put the position 134 >>> sum (1, 3)5 46 7 " "8 9 Ten defsum (A, b): One     " " A Docstrings can put the position 2 - >>> sum (3, 5) - 8 the      - >>> sum (' A ', ' C ') - ' AC ' -     " " +     returnA +b -      + if __name__=="__main__": A     Importdoctest atDoctest.testmod ()

Then we execute the command Python example.py-v in the console, and the result of the output test is as follows

$ python example.py-vtrying:    sum (1, 3) expecting:    4okTrying:    sum (3, 5) Expecting:    8okTrying:    sum (' A ', ' C ') Expecting:    ' ac ' ok2 items passed all tests:   1 Tests in __main__   2 tests in __main__.sum3 tests in 2 items.3 PA Ssed and 0 failed. Test passed.

Note that in the case where the sample is all passed, without failed, "Python example.py" is not outputting anything, it needs to add parameter-V to print all the test examples. We can replace the 5th line of examp.py with the wrong result 99, in the execution of "Python example.py", then we will show a sample that has not passed, as follows.

$ python example.py**********************************************************************"  example.py"in__main__Failed Example:    sum (1, 3) expected :    Got:    4**********************************************************************1 items had failures:    1 of in   __main__***test failed*** 1 failures.

It is also important to note that the document comments inside the

>>> sum (1, 3)

After ">>>" Remember to follow a space

Let's see it again.

if __name__ " __main__ " :     Import doctest    doctest.testmod ()

If you do not want to execute Testmod () in __main__, you can also do it without writing python-m doctest-v example.py.

2. Pass the test file tests

We create a new text file Example.txt, which writes

>>> from example Import sum>>> sum (2, 3) 5

Then replace the Testmod () function in example.py with the Testfile ()

Import doctestdoctest.testfile ("example.txt")

And then, like 1, run Python example.py-v

Similarly, if you do not want to run testfile () in example.py, you can also use the following command

Python-m doctest-v Example.txt

Resources:

Official Python document: https://docs.python.org/3/library/doctest.html

"Fluent Python"

\python36\lib\test\test_doctest.py

Python Test standard library doctest