Libvirt/libvirt node driver cleanup and tests

[Katana-Steel]

Extra tests for libvirt_driver and cleaner driver creation

Description

Code clean up and added more tests for the libvirt_driver module.
Cleaner driver creation with less console output when using SASL
authentication.

Status

• done, ready for review

Checklist (tick everything that applies)

• Code linting (required, can be done after the PR checks)
• Documentation
• Tests
• ICLA (required for bigger changes)

[Kami]

I'm fine with this code, but I believe you could also utilize Mock for that by specifying a class you want to mock for spec argument - http://www.voidspace.org.uk/python/mock/mock.html#mock.Mock.

This would mean less code to maintain and keep up to date :)

[Kami]

Thanks for this contribution.

I've added some comments. It would be great if you could at least update the tests to follow the same approach as other driver test (sorry for not mentioning in your first tests PR, I missed it :().

[Katana-Steel]

reviewed the suggestions and I did read up on Mock for testing
and updated the test code to mock essentially the entire libvirt module just to be safe ;)

[Katana-Steel]

the have_libvirt check makes using the mock framework hard when libvirt isn't installed.

I'll take any suggestions... I could go back to inherit and just use MagicMock for virConnection

it seems bad to assume libvirt is installed for tests to pass. Or would that be an acceptable change?

[Kami]

mock is already specified in requirements-tests.txt so no need to also specify it here.

In any case, not a big deal, I will remove it while merging :)

[Kami]

@Katana-Steel Ideally we can make it work without requiring libvirt to be installed, at least for the basic unit tests.

I'm fine with having additional integration tests which can require libvirt to be installed as long as those don't run by default if libvirt is not installed (we can use unittest.skipIf and skip if libvirt is not installed).

[Kami]

Thanks for making those changes.

I will make the mock change and get the tests passing locally and then merge it into trunk.

[Kami]

I made those changes and merged it into trunk - 01c6db4 , d9fc1ed, a4bddfe

Thanks!

[Kami]

Also - 6626808

Some time in the next couple of days when I get a chance I will look into running libvirt tests on Travis CI.

For one, we need to make sure all the system level libvirt dependencies are installed on Travis and after that we need to install libvirt library in all the virtual environments used by tox.

[Kami]

It looks like that Travis doesn't have libvirt system package whitelisted so sadly it doesn't look like we can get this easily to run on new Travis container based infrastructure :/

https://travis-ci.org/apache/libcloud/jobs/144437976#L118