- [x] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] If this is a bugfix. Have you checked that there is a bug report open for the issue you are trying to fix on [bug reports](https://bugs.launchpad.net/snapcraft)? - [x] If this is a new feature. Have you discussed the design on the [forum](https://forum.snapcraft.io)? - [x] Have you successfully run `./runtests.sh static`? - [x] Have you successfully run `./runtests.sh unit`? ----- As lxd.py has been growing continously I'm splitting it up into one file per class in its own module. That's the Containerbuild base class, Cleanbuilder and Project. I'm using the opportunity to move the Cleanbuilder-specific methods _push_file, _pull_file, _setup_project and _finish out of the Containerbuild class, where before the separation was poor. I'm also de-duplicating calls to set environment variables. Also as a side effect of this split I had to stop importing subprocess functions and sleep by name because unittest.mock couldn't override them for the whole module and patching all the individual files would have been complex and error prone. There's no change in functionality here.