@Test
 public void testLegal6() {
   assertFalse(b.legal(0, 0, Direction.DOWN));
 }
 @Test
 public void testLegal5() {
   assertFalse(b.legal(0, 0, Direction.LEFT));
 }
 @Test
 public void testLegal4() {
   assertFalse(b.legal(0, 0, Direction.UP));
 }
 @Test
 public void testLegal3() {
   assertTrue(b.legal(0, 2, Direction.LEFT));
 }
 @Test
 public void testLegal2() {
   assertFalse(b.legal(0, 2, Direction.RIGHT));
 }
 @Test
 public void testLegal() {
   assertTrue(b.legal(0, 0, Direction.RIGHT));
 }