Added unit tests to detect assignment errors - square completion and drawing lines twice

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -26,6 +26,30 @@ public class DotsAndBoxesGridTest {
         logger.info("Dummy test to show the test suite runs");
         assertTrue(true);
     }
+    @Test
+    public void testSquareCompletion() {
+        logger.info("Testing if square completion detection is working");
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3);
+        
+        // Simulate drawing lines to complete a square at (0,0)
+        grid.drawHorizontal(0, 0, 1);
+        grid.drawVertical(0, 0, 1);
+        grid.drawHorizontal(0, 1, 1);
+        grid.drawVertical(1, 0, 1);
+
+        // The square at (0,0) should be complete
+        assertTrue(grid.isSquareComplete(0, 0), "Square at (0,0) should be complete");
+    }
 
-    // FIXME: You need to write tests for the two known bugs in the code.
+    @Test
+    public void testDrawingLineTwiceThrowsException() {
+        logger.info("Testing if drawing a line twice throws an IllegalStateException");
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3);
+        
+        // Simulate drawing a horizontal line
+        grid.drawHorizontal(0, 0, 1);
+
+        // Try drawing the same horizontal line again, which should throw an IllegalStateException
+        assertThrows(IllegalStateException.class, () -> grid.drawHorizontal(0, 0, 1));
+    }
 }