Fixed error in boxCompleteDetectsCompletedBoxes test

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -38,7 +38,7 @@ public class DotsAndBoxesGridTest {
         case1.drawHorizontal(0, 0, 0);
         case1.drawVertical(0, 0, 1);
         case1.drawHorizontal(0, 1, 0);
-        case1.drawHorizontal(1, 0, 1);
+        case1.drawVertical(1, 0, 1);
 
         assertTrue(case1.boxComplete(0, 0));