Fix AppendGraph unit tests

src/models/append_graph.rs

@@ -214,7 +214,7 @@ mod tests {
         assert!(
             graph.are_adjacent(vertices[9], vertices[5]),
             "expected {:?} and {:?} to be adjacent",
-            vertices[0],
+            vertices[9],
             vertices[5]
         );
         assert!(
@@ -329,7 +329,7 @@ mod tests {
             Some(v),
             "vertex should be neighbor of itself twice"
         );
-        assert_eq!(neighbors.next(), None, "two many neighbors from iterator");
+        assert_eq!(neighbors.next(), None, "too many neighbors from iterator");
     }
 
     #[test]
@@ -368,7 +368,7 @@ mod tests {
             assert_eq!(
                 neighbors.next(),
                 None,
-                "two many neighbors of {:?} from iterator",
+                "too many neighbors of {:?} from iterator",
                 vertices[i]
             );
         }