Fix version-check.

[pillarsdotnet]

Fixes #303
Fixes #354
Fixes #420
Fixes #429
Fixes #444
Fixes #476

Allows Python3 installation on Centos-7 thusly:

class { 'python':
  version: 'python36'
}

[rnelson0]

The code looks functional, a few comments on layout/syntax. This would benefit from an additional test or two leveraging the new version string allowed, though.

[pillarsdotnet]

The code looks functional, a few comments on layout/syntax. This would benefit from an additional test or two leveraging the new version string allowed, though.

Made requested changes; added tests; waiting for them to pass.

[pillarsdotnet]

@rnelson0 -- Woo-hoo! Tests passed.

[rnelson0]

As mentioned in Slack, so many ::s :) But it works just fine! Looks like tests are passing so it should be good to go. Can you just add a note about whether you’ve tried using this locally, in a more complex environment, before merging?

[pillarsdotnet]

Removed :: prefixes as requested.

Yes, I'm using this locally to install requisites for pre-commit.

[jozsi]

This is actually breaking. If I specify version 3.7 or python3.7 (because the Ubuntu package is called python3.7), it matches the /\A(python)?([0-9]+)/ regular expression and the 2nd group matches only 3, so the .7 gets cut off in the package version.

[bastelfreak]

@jozsi thanks for pointing this out. Are you able to provide a PR with a test that matches this?

[jozsi]

@bastelfreak - I am away for a couple of days. I just used the latest "puppet-agent-ubuntu" docker image (now based on Ubuntu 18.04 Bionic) and provision with a puppet manifest that only contains puppet-python (v3.0.1) set to version "python3.7" or "3.7". Both gets interpreted as "python3" under the hood*, that is already satisfied by "python3.6" installed on the system, so no action is taken by ensure. * https://github.com/voxpupuli/puppet-python/blob/master/manifests/install.pp#L12