如何在PHPUnit测试用例中使用服务器变量？

我正在使用PHPUnit测试用例测试模块。所有的东西都工作正常，但是当我使用$_SERVER['REMOTE_ADDR']它时会出现致命错误并停止执行。

CategoryControllerTest.php

boot();
        $this->container = static::$kernel->getContainer();
        $this->em = static::$kernel->getContainer()->get('doctrine')->getManager();
    }

    public function testCategory() {
        $ip_address = $_SERVER['REMOTE_ADDR'];
        $client = static::createClient(
          array(), array('HTTP_HOST' => static::$kernel->getContainer()->getParameter('test_http_host')
        ));

        $crawler = $client->request('POST', '/category/new');
        $client->enableProfiler();

        $this->assertEquals('ProductBundle\Controller\CategoryController::addAction', $client->getRequest()->attributes->get('_controller'));
        $form = $crawler->selectButton('new_category')->form();
        $form['category[name]'] = "Electronics";
        $form['category[id]']   = "For US";
        $form['category[ip]']   = $ip_address;
        $client->submit($form);

        $this->assertTrue($client->getResponse()->isRedirect('/category/new')); // check if redirecting properly
        $client->followRedirect();
        $this->assertEquals(1, $crawler->filter('html:contains("Category Created Successfully.")')->count());
    }
}

错误

有1个错误：

1）ProductBundle \ Tests \ Controller \ CategoryControllerTest :: testCategory未定义的索引：REMOTE_ADDR

我试图将其添加到setUp()功能中，但效果不佳。