public function testAddTransaction()
 {
     $payment = new Payment($this->getInstruction(), 123);
     $transaction = new FinancialTransaction();
     $this->assertEquals(0, count($payment->getTransactions()));
     $payment->addTransaction($transaction);
     $this->assertEquals(1, count($payment->getTransactions()));
     $this->assertSame($transaction, $payment->getTransactions()->get(0));
     $this->assertSame($payment, $transaction->getPayment());
 }