Fix unit tests

src/optic_node.rs

@@ -77,7 +77,7 @@ mod test {
     #[test]
     fn to_dot() {
         let node = OpticNode::new("Test", Box::new(NodeDummy));
-        assert_eq!(node.to_dot(), "  \"Test\"\n".to_owned())
+        assert_eq!(node.to_dot(), "[label=\"Test\"]\n".to_owned())
     }
     #[test]
     fn node_type() {

src/optic_scenery.rs

@@ -135,7 +135,7 @@ mod test {
         scenery.add_node(OpticNode::new("Test", Box::new(NodeDummy)));
         assert_eq!(
             scenery.to_dot(),
-            "digraph {\n  label=\"SceneryTest\"\n  \"Test\"\n}"
+            "digraph {\n  label=\"SceneryTest\"\n  node_idx_0 [label=\"Test\"]\n}"
         );
     }
     #[test]