[yt-dev] Testing Intervention

[Anthony Scopatz]

Helo Casey,

Sorry for taking the whole weekend to respond.

I would like to help with this, but it's difficult to figure out where to
>> start.
>>
>
Not to worry. I think that any of the items listed at the bottom of Matt's
original email
would be a great place to start.


>
>> Say I want to test projections. I make a fake 3D density field, maybe
>> something as simple as np.arange(4**3).reshape((4, 4, 4)). I write down the
>> answer to the x-projection. Now all I need to do is call
>> assert_allclose(yt_result, answer, rtol=1e-15), but I don't know what
>> pieces of low-level yt stuff to call to get to `yt_result`. Hopefully
>> that's clear...
>>
>> Maybe this comes down to creating a fake frontend we can attach fields to?
>>
>
Actually, I disagree with this strategy, as I told Matt when we spoke last
week.
*What is important is that we test the science and math parts of the code *
*before, **if ever, dealing with the software architecture
that surrounds them. *
*
*
Let's taking your example of projections.  What we need to test is the
actual function
or method which actually slogs through the projection calculation.  In many
cases in
yt these functions are not directly attached to the front end but live in
analysis, visualization
or utilities subpackages.   It is these such packages that we should worry
about testing.
We can easily create routines to feed them sample data.

On the other hand, testing or mocking things like frontends should be a
very low priority.
At the end of the day what you are testing here is pulling in data from
disk or other
sources.  Effectively, this is just re-testing functionality present in
h5py, etc.  That is not
really our job.  Yes, in a perfect world, front ends would be tested too.
 But I think that the
priority should be placed on things like the KDTree.

Be Well
Anthony


>
>> - Casey
>>
>>
>> On Fri, Sep 21, 2012 at 2:42 PM, Matthew Turk <matthewturk at gmail.com>wrote:
>>
>>> Hi all,
>>>
>>> As some of you have seen (at least Stephen), I filed a ticket this
>>> morning about increasing testing coverage.  The other night Anthony
>>> and I met up in NYC and he had something of an "intervention" about
>>> the sufficiency of answer testing for yt; it didn't take too much work
>>> on his part to convince me that we should be testing not just against
>>> a gold standard, but also performing unit tests.  In the past I had
>>> eschewed unit testing simply because the task of mocking data was
>>> quite tricky, and by adding tests that use smaller bits we could cover
>>> unit testable areas with answer testing.
>>>
>>> But, this isn't really a good strategy.  Let's move to having both.
>>> The testing infrastructure he recommends is the nearly-omnipresent
>>> nose:
>>>
>>> http://nose.readthedocs.org/en/latest/
>>>
>>> The ticket to track this is here:
>>>
>>>
>>> https://bitbucket.org/yt_analysis/yt/issue/426/increase-unit-test-coverage
>>>
>>> There are a couple sub-items here:
>>>
>>> 1) NumPy's nose test plugins provide a lot of necessary functionality
>>> that we have reimplemented in the answer testing utilities.  I'd like
>>> to start using the numpy plugins, which include things like
>>> conditional test execution, array comparisons, "slow" tests, etc etc.
>>> 2) We can evaluate, using conditional test execution, moving to nose
>>> for answer testing.  But that's not on the agenda now.
>>> 3) Writing tests for nose is super easy, and running them is too.  Just
>>> do:
>>>
>>> nosetest -w yt/
>>>
>>> when in your source directory.
>>>
>>> 4) I've written a simple sample here:
>>>
>>>
>>> https://bitbucket.org/yt_analysis/yt-3.0/src/da10ffc17f6d/yt/utilities/tests/test_interpolators.py
>>>
>>> 5) I'll handle writing up some mock data that doesn't require shipping
>>> lots of binary files, which can then be used for checking things that
>>> absolutely require hierarchies.
>>>
>>> --
>>>
>>> The way to organize tests is easy.  Inside each directory with
>>> testable items create a new directory called "tests", and in here toss
>>> some scripts.  You can stick a bunch of functions in those scripts.
>>>
>>> Anyway, I'm going to start writing more of these (in the main yt repo,
>>> and this change will be grafted there as well) and I'll write back
>>> once the data mocking is ready.  I'd like it if we started encouraging
>>> or even mandating simple tests (and/or answer tests) for functionality
>>> that gets added, but that's a discussion that should be held
>>> separately.
>>>
>>> The items on the ticket:
>>>
>>>  * kD-tree for nearest neighbor
>>>  * Geometric selection routines
>>>  * Profiles
>>>  * Projections -- underlying quadtree
>>>  * Data object selection of data containers
>>>  * Data object selection of points
>>>  * Orientation class
>>>  * Pixelization
>>>  * Color maps
>>>  * PNG writing
>>>
>>> Is anyone willing to claim any additional items that they will help
>>> write unit tests for?
>>>
>>> -Matt
>>> _______________________________________________
>>> yt-dev mailing list
>>> yt-dev at lists.spacepope.org
>>> http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
>>>
>>
>>
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