ImportError: cannot import name 'isclose'

Question

I am running into a weird error when unit testing my Python module:

⅔ of the builds are passing normally, but one of them is failing to import isclose from the standard math library.

The error is reproduced below:

==================================== ERRORS ====================================
______________________ ERROR collecting tests/test_yau.py ______________________
ImportError while importing test module '/home/travis/build/Benjamin-Lee/squiggle/tests/test_yau.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
tests/test_yau.py:5: in <module>
    from math import isclose
E   ImportError: cannot import name 'isclose'
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!
=========================== 1 error in 0.29 seconds ============================
The command "pytest --cov=squiggle" exited with 2.

There is no file named math.py in the same directory (or at all in my package). What could be causing this?

Restarting the build multiple times has not fixed this error and it is only showing up in Python 3.4.

The full logs are accessible here.

Answer 1

pytest has the function approx for testing approximate equality of two numbers, available for any python version. The assertion

assert math.isclose(a, b, rel_tol=rt, abs_tol=at)

could be thus replaced with

assert a == pytest.approx(b, rel=rt, abs=at)