Unit tests added

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -28,4 +28,32 @@ public class DotsAndBoxesGridTest {
     }
 
     // FIXME: You need to write tests for the two known bugs in the code.
+    @Test
+    public void boxCompleteDetectsCompletedBoxes() {
+        // code to test that boxComplete returns true for boxes that *are complete* goes here
+        DotsAndBoxesGrid case1 = new DotsAndBoxesGrid(5, 5, 2);
+        case1.drawHorizontal(0, 0, 0);
+        case1.drawVertical(0, 0, 1);
+        case1.drawHorizontal(0, 1, 0);
+        case1.drawVertical(1, 0, 1);
+
+        assertTrue(case1.boxComplete(0, 0));
+    }
+    @Test
+    public void drawMethodsDetectRedrawnLines() {
+        DotsAndBoxesGrid case2 = new DotsAndBoxesGrid(5, 5, 2);
+        case2.drawHorizontal(0, 0, 0);
+        case2.drawVertical(0, 0, 1);
+
+        // code to test that drawHorizontal throws an exception if the line was already drawn goes here
+        assertThrows(IllegalStateException.class, () -> {
+            case2.drawHorizontal(0, 0, 1); // divide by zero throws an exception for int/int
+        });
+
+        // code to test that drawVertical throws an exception if the line was already drawn goes here
+        assertThrows(IllegalStateException.class, () -> {
+            case2.drawVertical(0, 0, 0); // divide by zero throws an exception for int/int
+        });
+
+    }
 }