do_the_walk may be generic now?

src/renderer/renderer.rs

@@ -136,7 +136,7 @@ mod tests {
         }
     }
 
-    fn do_the_walk<'a>(c: &'a (dyn Walkable<Output = &str>), path: &str) -> &'a str {
+    fn do_the_walk<'a, O: Walkable>(c: &'a dyn Walkable<Output = O>, path: &str) -> &'a O {
         c.walk(path)
     }
 
@@ -147,6 +147,10 @@ mod tests {
                 .iter()
                 .cloned()
                 .collect();
-        assert_eq!(do_the_walk(&context, "cat"), "kitty");
+        let number_context: HashMap<&str, u32> = [("cat", 1), ("dog", 2), ("tiger", 3)]
+            .iter()
+            .cloned()
+            .collect();
+        assert_eq!(do_the_walk(&context, "cat"), &"kitty");
     }
 }