@Test(expected = IllegalStateException.class)
 public void testUpdateOutgoingEdge_NonExistentEdge() throws Exception {
   Node node =
       new ByteArrayNodeNonLeafVoidValue(
           "FOO",
           Arrays.asList(
               (Node) new ByteArrayNodeDefault("BAR", 1, Collections.<Node>emptyList())));
   node.updateOutgoingEdge(new ByteArrayNodeDefault("CAR", null, Collections.<Node>emptyList()));
 }
 @Test
 public void testUpdateOutgoingEdge() throws Exception {
   Node node =
       new ByteArrayNodeNonLeafVoidValue(
           "FOO",
           Arrays.asList(
               (Node) new ByteArrayNodeDefault("BAR1", 1, Collections.<Node>emptyList())));
   node.updateOutgoingEdge(new ByteArrayNodeDefault("BAR2", null, Collections.<Node>emptyList()));
 }