Tests for pygraphviz
--------------------

>>> from pygraphviz import *

>>> A=Agraph()
>>> nodelist=['a','b','c','d','e']
>>> edgelist=[['a','b'],['a','a'],['c','d']]

>>> ids=[A.add_node(n) for n in nodelist]
>>> len(ids)==len(nodelist)
True

>>> ids= [A.add_edge(source,target,None) for (source,target) in edgelist]
>>> len(ids)==len(edgelist)
True

>>> for n in sorted(A.nodes()):
...    print n
a
b
c
d
e

>>> for e in sorted(A.edges()):
...    print e.source(),e.target()
a b
a a
c d

>>> print A.is_undirected()
True

>>> print A.is_directed()
False

