Commit 2c9f6f0

@@ -46,9 +46,9 @@ public class MovingRobot extends Robot {
   }
 
   public String printMoves() {
-    String printer = "";
-    for (Integer move : this.moves) printer += String.format("%d", move);
-    return printer;
+    ArrayList<String> printableMoves = new ArrayList<String>();
+    for (Integer move : this.moves) printableMoves.add(String.valueOf(move));
+    return String.join(",", printableMoves);
   }
 
   public void move() {

@@ -133,4 +133,14 @@ public class MovingRobotTest extends TestCase {
     assertEquals(0, subject.getX());
     assertEquals(0, subject.getY());
   }
+
+  public void test_printMoves() {
+    subject = new MovingRobot(0, 0);
+
+    subject.move(Robot.RIGHT);
+    assertEquals(String.format("%d", Robot.RIGHT), subject.printMoves());
+
+    subject.move(Robot.RIGHT);
+    assertEquals(String.format("%d,%d", Robot.RIGHT, Robot.RIGHT), subject.printMoves());
+  }
 }