// test the worldEnd method
 void testWorldEnd(Tester t) {
   t.checkExpect(ctf.worldEnds().worldEnds, false);
   resetCTF();
   ctf.player.score = 300000;
   t.checkExpect(ctf.worldEnds().worldEnds, true);
   resetCTF();
   ctf.player.hunger = 0;
   t.checkExpect(ctf.worldEnds().worldEnds, true);
   resetCTF();
   ctf.player.speed = 0;
   t.checkExpect(ctf.worldEnds().worldEnds, true);
 }
 // test the onKeyEvent method
 void testOnKeyEvent(Tester t) {
   ctf.onKeyEvent(" ");
   t.checkExpect(ctf.isJumping, true);
 }
 // test the removePowerups method
 void removePowerups(Tester t) {
   ctf.removePups(0);
   t.checkExpect(ctf.field.pUps, new ArrayList<Powerup>());
 }
 // test the onTick method
 void testOnTick(Tester t) {
   resetCTF();
   ctf.onTick();
   t.checkExpect(ctf.player.loc, new Posn(6, CollectTheFruit.height - 30));
 }
 // test the hitPowerup method
 void testHitPowerup(Tester t) {
   t.checkExpect(ctf.hitPowerup(), -1);
   ctf.field.addPowerup(0, CollectTheFruit.height - 30);
   t.checkExpect(ctf.hitPowerup(), 0);
 }