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On the other hand, as expected, the call to the sum function is shown as failed . As before, both the location and the nature of the failure is explained.

Embedding a test in a docstring

As mentioned earlier , in addition to putting tests in separate text files, you can also embed tests in docstrings.

What is a docstring?

As shown in the earlier module titled Itse1359-1270-Functions , and described more fully in What is a Docstring? , a docstring is a string literal that occurs as the first statement in a module, function, class, or method definition. A docstring is surrounded bytriple quotes.

The module named Py1359_1720_03

This example will perform a test on a simple function named sum in a module named Py1359_1720_03.py as shown in Listing 6 .

Listing 6 . Contents of the file named Py1359_1720_03.py.
""">>>sum(2,3) 6""" def sum(parA,parB):return parA + parB if __name__ == "__main__":import doctest doctest.testmod()

Listing 6 is an update of the earlier module shown in Listing 3 . Test code was embedded in the docstring at the beginning of Listing 6 .

In addition, a special if statement was added at the end of Listing 6 that calls the testmod function of the doctest module. (See the earlier comment regarding the testmod function and the command line shortcut.)

According to The Python Standard Library -- 26.2.1. Simple Usage: Checking Examples in Docstrings , if you include this code at the end of a module, running the module as a script will cause tests that are embedded in docstrings to be executed.

Detailed information on the various options of the testmod function are provided at The Python Standard Library -- 26.2.4. Basic API .

The batch file named Py1359_1720_03

The batch file used to execute the test is shown in Listing 7 .

Listing 7 . Contents of the batch file named Py1359_1720_03.bat.
echo off rem set the pathpath=%path%;"C:\Program Files (x86)\Python34" rem perform the testpython Py1359_1720_03.py -v pause

In this case there was no separate test file. Instead, the python command in Listing 7 executed the module named Py1359_1720_03.py as a script triggering the test to be run as described above .

The output

The -v switch in Listing 7 causes the verbose version of the output to be produced as shown in Figure 4 . Once again, I set the test up in such a way as to cause it to fail for purposes of illustration.

Figure 4 . Output produced by the test embedded in the docstring.
Trying: sum(2,3)Expecting: 6********************************************************************** File "Py1359_1720_03.py", line 4, in __main__Failed example: sum(2,3)Expected: 6Got: 51 items had no tests: __main__.sum********************************************************************** 1 items had failures:1 of 1 in __main__ 1 tests in 2 items.0 passed and 1 failed. ***Test Failed*** 1 failures.

Run the program

I encourage you to copy the code provided in this module. Execute the code and confirm that you get the same results. Experiment with the code,making changes, and observing the results of your changes. Make certain that you can explain why your changes behave as they do.

What's next?

Now that you know some of the mechanics of using doctest , you should study the next module in the collection titled Itse1359-1720r-Review . In addition, you should study some of the many articles andtutorials that are freely available on the web that provide insight into the use of doctest for unit testing. Links to a few of those documents are provided below. You canfind many more with a simple web search.


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Itse1359-1720-Doctest Introduction
  • File: Itse1359-1720.htm
  • Published: 11/10/14
  • Revised: 03/04/15

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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