diff --git a/test/preflow_graph.lgf b/test/preflow_graph.lgf
new file mode 100644
--- /dev/null
+++ b/test/preflow_graph.lgf
@@ -0,0 +1,35 @@
+@nodes
+label	
+0	
+1	
+2	
+3	
+4	
+5	
+6	
+7	
+8	
+9	
+@edges
+		label	capacity	
+0	1	0	20	
+0	2	1	0	
+1	1	2	3	
+1	2	3	8	
+1	3	4	8	
+2	5	5	5	
+3	2	6	5	
+3	5	7	5	
+3	6	8	5	
+4	3	9	3	
+5	7	10	3	
+5	6	11	10	
+5	8	12	10	
+6	8	13	8	
+8	9	14	20	
+8	1	15	5	
+9	5	16	5	
+@attributes 
+source 1
+target 8
+@end