hasDiscount() public method

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