public function testVoid()
{
$request = $this->gateway->void(array('transactionReference' => 'abc123'));
$this->assertInstanceOf('\\Omnipay\\PayPal\\Message\\RestVoidRequest', $request);
$this->assertSame('abc123', $request->getTransactionReference());
$endPoint = $request->getEndpoint();
$this->assertSame('https://api.paypal.com/v1/payments/authorization/abc123/void', $endPoint);
$data = $request->getData();
$this->assertEmpty($data);
}