public function testIsRedemptionCountValid()
 {
     $this->promotion->setMaxRedemptions(null);
     $this->assertTrue($this->promotion->isRedemptionCountValid());
     $this->promotion->setMaxRedemptions(10);
     $this->promotion->setRedemptions(0);
     $this->assertTrue($this->promotion->isRedemptionCountValid());
     $this->promotion->setRedemptions(9);
     $this->assertTrue($this->promotion->isRedemptionCountValid());
     $this->promotion->setRedemptions(10);
     $this->assertFalse($this->promotion->isRedemptionCountValid());
     $this->promotion->setRedemptions(15);
     $this->assertFalse($this->promotion->isRedemptionCountValid());
 }