diff -r 07cd9a2d20e0 -r ce1533650f7d test/min_cost_flow_test.cc
--- a/test/min_cost_flow_test.cc	Mon Jul 07 11:23:41 2014 +0200
+++ b/test/min_cost_flow_test.cc	Mon Jul 07 15:40:12 2014 +0200
@@ -395,6 +395,12 @@
   mcf3.upperMap(neg2_u);
   checkMcf(mcf3, mcf3.run(param), neg2_gr, neg2_l, neg2_u, neg2_c, neg2_s,
            mcf3.OPTIMAL, true,     -300, test_str + "-18", GEQ);
+
+  // Tests for empty graph
+  Digraph gr0;
+  MCF mcf0(gr0);
+  mcf0.run(param);
+  check(mcf0.totalCost() == 0, "Wrong total cost");  
 }
 
 template < typename MCF, typename Param >