public function testGetAccessToken()
{
$cred = new OAuthTokenCredential(Constants::CLIENT_ID, Constants::CLIENT_SECRET);
$this->assertEquals(Constants::CLIENT_ID, $cred->getClientId());
$this->assertEquals(Constants::CLIENT_SECRET, $cred->getClientSecret());
$config = PayPalConfigManager::getInstance()->getConfigHashmap();
$token = $cred->getAccessToken($config);
$this->assertNotNull($token);
// Check that we get the same token when issuing a new call before token expiry
$newToken = $cred->getAccessToken($config);
$this->assertNotNull($newToken);
$this->assertEquals($token, $newToken);
}