Laravel\Cashier\Invoice::hasDiscount PHP Method

    public function hasDiscount()
    {
        return count($this->transaction->discounts) > 0;
    }

 public function testHasDiscountIndicatesIfTotalDiscountWasApplied()
 {
     $invoice = new Invoice(m::mock('Laravel\\Cashier\\Contracts\\Billable'), (object) ['total' => 0, 'subtotal' => 20000, 'discount' => 100]);
     $this->assertTrue($invoice->hasDiscount());
 }