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I'm developing a program that makes some floating points calculations. Is there any way to test my functions (which deliver floats) with doctests?
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There are several common ways to use doctest: To check that a module's docstrings are up-to-date by verifying that all interactive examples still work as documented. To perform regression testing by verifying that interactive examples from a test file or a test object work as expected.
When the tests include values that are likely to change in unpredictable ways, and where the actual value is not important to the test results, you can use the ELLIPSIS option to tell doctest to ignore portions of the verification value.
doctest is a module included in the Python programming language's standard library that allows the easy generation of tests based on output from the standard Python interpreter shell, cut and pasted into docstrings.
Sure, just format the floats with a reasonable format, based on your knowledge of what precision you expect them to exhibit -- e.g, if you expect accuracy to 2 digits after the decimal point, you could use:
''' Rest of your docstring and then...
>>> '%.2f' % funcreturningfloat()
'123.45'
'''
The documentation has a suggestion
Floating-point numbers are also subject to small output variations across platforms, because Python defers to the platform C library for float formatting, and C libraries vary widely in quality here.
>>> 1./7 # risky
0.14285714285714285
>>> print 1./7 # safer
0.142857142857
>>> print round(1./7, 6) # much safer
0.142857
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