Add further unit tests.

src/optic_node.rs

@@ -8,16 +8,18 @@ impl OpticNode {
     pub fn new(name: String) -> Self {
         Self { name }
     }
-
     /// Sets the name of this [`OpticNode`].
     pub fn set_name(&mut self, name: String) {
         self.name = name;
     }
-
     /// Returns a reference to the name of this [`OpticNode`].
     pub fn name(&self) -> &str {
         self.name.as_ref()
     }
+    /// Returns a string representation of the [`OpticNode`] in `graphviz` format.
+    pub fn to_dot(&self) -> String {
+        format!("  {}\n", self.name)
+    }
 }
 
 #[cfg(test)]
@@ -39,4 +41,9 @@ mod test {
         let node = OpticNode::new("Test".into());
         assert_eq!(node.name(), "Test".to_owned())
     }
+    #[test]
+    fn to_dot() {
+        let node = OpticNode::new("Test".into());
+        assert_eq!(node.to_dot(), "  Test\n".to_owned())
+    }
 }

src/optic_scenery.rs

@@ -53,6 +53,12 @@ mod test {
         assert_eq!(scenery.g.node_count(),0);
     }
     #[test]
+    fn add_node() {
+        let mut scenery= OpticScenery::new();
+        scenery.add_node(OpticNode::new("Test".into()));
+        assert_eq!(scenery.g.node_count(),1);
+    }
+    #[test]
     fn to_dot() {
         let mut scenery=OpticScenery::new();
         scenery.set_description("Test".into());