[matplotlib-devel] Image comparison decorators outside matplotlib

[Eduard B. <edu...@ae...>]

Hello,

I am developing a toolkit to parse, analyse and plot some scientific
data using matplotlib. Among them are some application-specific plotting
functions that sort of extend matplotlib.

There are these nice image comparison decorators to test code like that
but I am not sure how to use them for unit testing outside the scope of
matplotlib itself. Is this use case intended and possible for the decorator?

I have experimented with this unsuccessfully in the following way:

There is a tests directory within my package with test functions
decorated like so

@image_comparison(baseline_images=['custom_function'])
def test_custom_function():
    # plot stuff...

When I run nosetests, it fails creating some output images in
result_images.

Copying the appropriate files according to [1] to
my_package/tests/baseline_images does not seem to have any effect. There
are neither *-expected* nor *_{pdf,svg}.png files in there, only
custom_function.{pdf,svg,png}. What am I doing wrong?

Eduard

[1] http://matplotlib.org/devel/testing.html