Using multiple Python versions

Build Environment
1

I’m in a rather awkward situation where my application is written in Python 3 but the script that mocks some testing data depends on Python 2. Unfortunately, migrating to Python 3 is no small task and I won’t be able to make the time to do it for a while. Is there a way to use both Python versions within my tests?

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2

There are a few options to achieve that, you can find the examples right here.

3

You should be able to reference explicit versions of Python in your tests by using python2.7 instead of python which will run the specific version of Python instead of the symlinked default version.

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4

When I run python2.7, I get the following error:

python2.7 db/generate.py user=ubuntu dbname=circle_test
pyenv: python2.7: command not found

The `python2.7' command exists in these Python versions:
  2.7
  2.7.10
  2.7.3
  2.7.4
  2.7.5
  2.7.6
  2.7.7
  2.7.8

Choosing one of those versions results in:

python2.7.10 db/generate.py user=ubuntu dbname=circle_test returned exit code 127

bash: line 1: python2.7.10: command not found Action failed: python2.7.10 db/generate.py user=ubuntu dbname=circle_test
5

ugh, it’s only letting you pick from the python binaries that are in the pyenv configuration.

I know that python 2.7.* is installed within the pyenv environment but the question is how do we get your current shell to let you break out of the pyenv sandbox and run the version you specify.

I’m going to ping the other support folks to talk about this.

6

I’m dealing with a similar situation. Has a solution been found for this?

1 Like
7

A method I’ve started to use is to put into the pre section the pyenv install #.#.# steps for what I want to use and then have a pyenv global #.#.# #.#.# that lists them all

You can see this in action here https://github.com/bear/parsedatetime/blob/master/circle.yml

8

It seems one of our other community members has run into this very issue and has written a blog post about it - you should check it out – https://ben.fogbutter.com/2016/02/20/testing-multiple-python-versions-on-circleci.html