doctests for planarity code #4509
Description
I'm still seeing the same segfault that I worked around in the patch on #4505. Here is code that triggers it for me.
sage: import networkx.generators.atlas # long time
sage: atlas_graphs = [Graph(i) for i in networkx.generators.atlas.graph_atlas_g()] # long time
sage: a = [i for i in [1..1252] if atlas_graphs[i].is_planar()] # long time
sage: b = [i for i in [1..1252] if atlas_graphs[i].is_planar()] # long time
I've added that as a doctest to the planarity code.
For me, the segfault usually happens on the second run (the "b =" line), but occasionally happens on the first run.
Component: graph theory
Author: Jason Grout
Reviewer: Tom Boothby, Minh Van Nguyen
Merged: sage-4.4.alpha0
Issue created by migration from https://trac.sagemath.org/ticket/4509