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There are at least two different ways to use doctest :

  1. You can write the test code in a separate text file and use that file to perform the testing.
  2. You can embed the test code in one or more docstrings in a module and cause the test code to be executed each time you execute the module as ascript.

A simple example of each approach will be provided and explained in this module.

Discussion and sample code

An interactive session

Figure 1 shows a simple interactive session run on the Python interactive command line interface.

Figure 1 . Simple interactive session.
>>>2 + 3 5>>>

If you have forgotten what the text in Figure 1 means, see the earlier module titled Itse1359-1010-Getting Started .

An automated interactive session

This first example is provided solely to show how doctest works. It is not intended to be useful otherwise.

The test file named Py1359_1720_01

Listing 1 shows the contents of a test file named Py1359_1720_01.txt .

Listing 1 . Contents of the test file named Py1359_1720_01.txt.
>>>2 + 3 6

Note that the contents of the test file mirror the input and the output of the interactive session shown in Figure 1 except that the result of performing the computation was purposely specified incorrectly as 6 instead of 5. (When you create a doctest test file, you must specify the required output as shown in Listing 1 .)

Note that the doctest process is very picky regarding file names. Some file names that are valid for the operating system may not work when using doctest . However, if you restrict your file names to names that would be valid for variables, you should be okay.

Listing 2 shows the contents of a Windows batch file named Py1359_1720_01.bat that I used to perform the test. Although not a requirement, the use of such a batch file makes it convenient to performthe test more than once with a minimal typing effort.

The batch the named Py1359_1720_01

Listing 2 . Contents of the file named Py1359_1720_01.bat.
echo off rem set the pathpath=%path%;"C:\Program Files (x86)\Python34" rem perform the testpython -m doctest Py1359_1720_01.txt pause

(Some of the text in Listing 2 is peculiar to my machine. You can ignore the text shown in Listing 2 down to the command that begins with the word python .)

The third command that begins with the word python in Listing 2 executes the Python doctest module as a script and passes the name of the test file as a command-lineargument to the module.

According to Python v3.1.5 documentation -- Python Setup and Usage , "When called with -m module-name, the given module is located on the Python module path and executed as a script."

The syntax shown for the python command in Listing 2 is a command line shortcut for calling the testmod() function in the doctest module. (You will see more on this later.)

The output

The execution of the python command in Listing 2 produced the command line output shown in Figure 2 .

Figure 2 . Output produced by the test filenamed Py1359_1720_01.txt.
********************************************************************** File "Py1359_1720_01.txt", line 2, in Py1359_1720_01.txtFailed example: 2 + 3Expected: 6Got: 5********************************************************************** 1 items had failures:1 of 1 in Py1359_1720_01.txt ***Test Failed*** 1 failures.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Itse 1359 introduction to scripting languages: python. OpenStax CNX. Jan 22, 2016 Download for free at https://legacy.cnx.org/content/col11713/1.32
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