Add support for conditional Skipping of unittests

[Rohit Karajgi]

Currently the unit-test code does not support skipIf(condition). Only a nose.skip plugin is used for skipping tests. More flexibility is required for skipping tests.

We need to have this support for situations where a unit test needs to be skipped due to module errors. Eg. Skip a test if libvirt/libxml2 is not installed.
A decorator can be written for skipIf and provided to the test classes.

This support is available in the unittest2 library

[Thierry Carrez (ttx)]

This was tried by Brian Lamar in https://code.launchpad.net/~blamar/nova/libvirt-cleanup-branch/+merge/66064

See the last comment from Monty: unfortunately skipIf is throwing a SkipTest error, which breaks our test harness. So this needs some extra care. Note that we already do conditional skipping with skip_test... is there a specific feature missing there ?

[Rohit Karajgi (rohitk)]

Thanks ttx. There should be someway to work around that error, since skipIf() can be handy.

This bug is linked to Brian's blueprint. I too feel that moving to unittest2 is necessary for additional support of skipIf and more features.

Based on this, my branch (lp:~rohitkarajgi/nova/libvirt_unittests) should get merged only after Brian's libvirt_refactoring branch is merged, to incorporate usage of unittest2.skipIf().

[Thierry Carrez (ttx)]

Sure, don't hesitate to lend a hand to Brian on this one by suggesting a solution, since he is busy on other things and this blocks your branch as well...

[Justin Shepherd (jshepher)]

Merge-prop pending resolution to lp:818210, as without venv I can not run any tests to ensure everything is working.