diff --git a/tbn.rkt b/tbn.rkt
index 38d56ca..cac0aa5 100644
--- a/tbn.rkt
+++ b/tbn.rkt
@@ -544,7 +544,7 @@
     (define sbn (hash 'a (tbf/state (hash 'b 2) 0)
                       'b (tbf/state (hash 'a 2) 0)))
     (check-equal? (graphviz (sbn-interaction-graph sbn))
-                  "digraph G {\n\tnode0 [label=\"b\"];\n\tnode1 [label=\"a\"];\n\tsubgraph U {\n\t\tedge [dir=none];\n\t\tnode0 -> node1 [label=\"2\"];\n\t\tnode0 -> node0 [label=\"0\"];\n\t\tnode1 -> node1 [label=\"0\"];\n\t}\n\tsubgraph D {\n\t}\n}\n")))
+                  "digraph G {\n\tnode0 [label=\"a\"];\n\tnode1 [label=\"b\"];\n\tsubgraph U {\n\t\tedge [dir=none];\n\t\tnode0 -> node1 [label=\"2\"];\n\t\tnode0 -> node0 [label=\"0\"];\n\t\tnode1 -> node1 [label=\"0\"];\n\t}\n\tsubgraph D {\n\t}\n}\n")))
 
 (: parse-org-tbn (->* ((Listof (Listof (U Symbol Real))))
                       (#:headers Boolean