Re: [matplotlib-devel] Comparing pdf output in tests

[Andrew S. <str...@as...>]

John Hunter wrote:
> On Wed, Sep 23, 2009 at 12:42 PM, Andrew Straw <str...@as...> wrote:
>
>   
>> Sorry, I should have been more clear. I was thinking that the
>> image_compare() decorator would call the test function multiple times,
>> having switched the backend between invocations. Thus, the call to
>> savefig() would continue not to explicitly set the extension. I've
>> quickly modified the source to reflect my idea, but I haven't had a
>> chance to flesh it out or test it. It should show the idea, though. See
>> attached.
>>     
>
> Why not have the decorator pass the extension in to the test funcs --
> agg can print to pdf, ps, svg and png
>   
I'm not sure what you're suggesting. Presumably if we're driving agg OK
to draw .png, it will also draw .pdf OK (or does it have a pdf vector
backend independent of the MPL pdf backend that we want to test separately?)

I was just thinking it would be easiest to have test functions that look
like:

@image_comparison('my_figure')
def my_figure_test():
    plt.plot([1,2,3],[4,5,6])
    plt.savefig('my_figure')

This could automatically test all backends we have the infrastructure
and the baseline images for. It doesn't force the test writer to worry
about that stuff.

-Andrew