Resolve "Fix errors in assignment"

Closes #1 (closed)

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -28,4 +28,60 @@ public class DotsAndBoxesGridTest {
     }
 
     // FIXME: You need to write tests for the two known bugs in the code.
+    @Test
+    public void testBoxCompleteFull() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        grid.drawHorizontal(0, 0, 1);
+        grid.drawHorizontal(0, 1, 1);
+        grid.drawVertical(0, 0, 1);
+        grid.drawVertical(1, 0, 1);
+
+        assertTrue(grid.boxComplete(0, 0));
+    }
+
+    @Test
+    public void testBoxCompletePartial() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        grid.drawHorizontal(1, 1, 1);
+        grid.drawVertical(1, 1, 1);
+        grid.drawVertical(2, 1, 1);
+
+        assertFalse(grid.boxComplete(1, 1));
+    }
+
+    @Test
+    public void testDrawVerticalOnce() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        assertFalse(grid.drawVertical(1, 1, 1));
+    }
+
+    @Test
+    public void testVerticalCannotBeRedrawn() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        grid.drawVertical(1, 1, 1);
+
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> {
+            grid.drawVertical(1, 1, 2);
+        });
+
+        assertTrue(exception instanceof IllegalArgumentException);
+    }
+
+    @Test
+    public void testDrawHorizontalOnce() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        assertFalse(grid.drawHorizontal(1, 1, 1));
+    }
+
+    @Test
+    public void testHorizontalCannotBeRedrawn() {
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
+        grid.drawHorizontal(1, 1, 1);
+
+        Exception exception = assertThrows(IllegalStateException.class, () -> {
+            grid.drawHorizontal(1, 1, 2);
+        });
+
+        assertTrue(exception instanceof IllegalArgumentException);
+    }
 }