Created unit tests for CompleteBox and Exception throws on existing line

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -28,4 +28,43 @@ public class DotsAndBoxesGridTest {
     }
 
     // FIXME: You need to write tests for the two known bugs in the code.
+
+    @Test
+    public void testBoxComplete() {
+
+        logger.info("This test sets up a test square 10,10,2 and draws a box for player1");
+
+        // set up the test box
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(10,10,2);
+
+        // draw a test square, player 1
+        grid.drawHorizontal(0,0,1);
+        grid.drawHorizontal(0,1,1);
+        grid.drawVertical(0,0,1);
+        grid.drawVertical(1,0,1);
+
+        assertAll(
+                // complete box
+                () -> assertTrue(grid.boxComplete(0,0)),
+                // incomplete box
+                () -> assertFalse(grid.boxComplete(1,1))
+        );
+    }
+
+    @Test
+    public void testDrawLine() {
+
+        logger.info("Dummy test to show the Exception test runs");
+
+        // set up the test box
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(10,10,2);
+
+        // draw a test line, player 1
+        grid.drawHorizontal(0,0,1);
+        grid.drawVertical(0,0,1);
+
+        // redraw lines to throw the exceptions
+        assertThrows(IllegalStateException.class, () -> grid.drawHorizontal(0,0,1));
+        assertThrows(IllegalStateException.class, () -> grid.drawVertical(0,0,1));
+    }
 }
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