diff --git a/test/digraph_test.cc b/test/digraph_test.cc
--- a/test/digraph_test.cc
+++ b/test/digraph_test.cc
@@ -35,6 +35,9 @@
   checkGraphNodeList(G, 0);
   checkGraphArcList(G, 0);
 
+  G.reserveNode(3);
+  G.reserveArc(4);
+
   Node
     n1 = G.addNode(),
     n2 = G.addNode(),