public function testGetSetTransactionKey()
{
$this->assertNull($this->paymentGateway->getTransactionKey());
$value = '111111';
$this->paymentGateway->setTransactionKey($value);
$this->assertEquals($value, $this->paymentGateway->getTransactionKey());
$config = array('transactionKey' => '222222');
$gateway = new PaymentGateway($config);
$this->assertEquals($config['transactionKey'], $gateway->getTransactionKey());
}
