RED: test all ones

test/bowling_game_test.dart

@@ -12,5 +12,15 @@ void main() {
 
       expect(game.score(), 0);
     });
+
+    test('all ones - score is 20', () {
+      final game = BowlingGame();
+
+      for (int i = 0; i < 20; i++) {
+        game.roll(1);
+      }
+
+      expect(game.score(), 20);
+    });
   });
 }