README for test Part 4

README.md

@@ -22,9 +22,11 @@ the test suit with more tests of your own.
     `runner.py` including creating a runner, turn, and move the runner forward.
   - `test_maze.py`: Some unit tests for testing the functionality of the `Maze`
     class, including creating a maze, add horizontal and vertical walls.
-  - `test_maze_runner`: Some unit tests for testing the functionality of the
+  - `test_maze_runner.py`: Some unit tests for testing the functionality of the
     runner to explore the maze including sensing the walls and turning left,
     right and to go straight.
+  - `test_shortest_path.py`: Some unit tests for testing the `shortest_path`
+    function (in `maze.py` for Part 4).
 
 - More tests will be added as the coursework specification evolves.