longest_path broken for digraphs

[mhansen]

sage: g = graphs.CompleteGraph(5).to_directed()
sage: g.longest_path(s=1,t=2)
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/home/mike/src/Imaging-1.1.7/<ipython-input-88-bddf7e1e9edc> in <module>()
----> 1 g.longest_path(s=Integer(1),t=Integer(2))

/opt/sage/local/lib/python2.6/site-packages/sage/graphs/generic_graph.pyc in longest_path(self, s, t, use_edge_labels, algorithm, solver, verbose)
   4772             (s is not None and (
   4773                     (s not in self) or
-> 4774                     (self._directed and self.degree_out(s) == 0) or
   4775                     (not self._directed and self.degree(s) == 0))) or
   4776             (t is not None and (

AttributeError: 'DiGraph' object has no attribute 'degree_out'

Apply trac_13019.patch

[ncohen]

Oh, right... We updated degree_out later on, and it looks like we did not add a doctest for digraphs :-)

Nathann

[ncohen]

Here it is ! :-)

Nathann

[mhansen]

Looks good to me.