Add igraph test (#1029)

Author: rosbo

tests/test_igraph.py

@@ -0,0 +1,12 @@
+import unittest
+
+from igraph import Graph
+
+
+class TestIgraph(unittest.TestCase):
+    def test_graph(self):
+        # Create a graph with 10 vertices & 2 children each.
+        g2 = Graph.Tree(n=10, children=2) 
+       
+        self.assertEqual(9, len(g2.get_edgelist()))
+