👍 IMHO it's a bug that the previous code did not raise an error. It's basically comparing a valid pdf to a empty image as far as I can see

The weak place is for fignum, baseline in zip(plt.get_fignums(), self._baseline_images):. zip shrinks lists to the size of the smallest. I am working on a refactor of image_comparison decorator and the issue come up on several tests, but this one was the most surprising.

Thanks @Kojoley good to know