Open Stack

On Tue, Feb 13, 2018 at 05:48:32PM -0500,
Assaf Muller <assaf at redhat.com> wrote:

> On Wed, Dec 13, 2017 at 7:30 AM, Michel Peterson <michel at redhat.com> wrote:
> > Through my work in networking-odl I've found what I believe is an issue
> > present in a majority of ML2 drivers. An issue I think needs awareness so
> > each project can decide a course of action.
> >
> > The issue stems from the adopted practice of importing
> > `neutron.tests.unit.plugins.ml2.test_plugin` and creating classes with noop
> > operation to "inherit" tests for free [1]. The idea behind is nice, you
> > inherit >600 tests that cover several scenarios.
> >
> > There are several issues of adopting this pattern, two of which are
> > paramount:
> >
> > 1. If the mechanism driver is not loaded correctly [2], the tests then don't
> > test the mechanism driver but still succeed and therefore there is no
> > indication that there is something wrong with the code. In the case of
> > networking-odl it wasn't discovered until last week, which means that for >1
> > year it this was adding PASSed tests uselessly.
> >
> > 2. It gives a false sense of reassurance. If the code of those tests is
> > analyzed it's possible to see that the code itself is mostly centered around
> > testing the REST endpoint of neutron than actually testing that the
> > mechanism succeeds on the operation it was supposed to test. As a result of
> > this, there is marginally added value on having those tests. To be clear,
> > the hooks for the respective operations are called on the mechanism driver,
> > but the result of the operation is not asserted.
> >
> > I would love to hear more voices around this, so feel free to comment.
> >
> > Regarding networking-odl the solution I propose is the following:
> >   **First**, discard completely the change mentioned in the footnote #2.
> >   **Second**, create a patch that completely removes the tests that follow
> > this pattern.
> 
> An interesting exercise would be to add 'raise ValueError' type
> exceptions in various ODL ML2 mech driver flows and seeing which tests
> fail. Basically, if a test passes without the ODL mech driver loaded,
> or with a faulty ODL mech driver, then you don't need to run the test
> for networking-odl changes. I'd be hesitant to remove all tests
> though, it's a good investment of time to figure out which tests are
> valuable to you.

Mike and Michel should raise it at the PTG for discussion.
I know Mike will attend.

thanks,
-- 
Isaku Yamahata <isaku.yamahata at gmail.com>