PHP，带有Behat和Mink的BDD（Selenium2驱动程序）：如何在测试结束时以编程方式关闭浏览器窗口？

我正在尝试使用Behat和Mink在PHP中学习BDD，并且我正在使用Selenium2驱动程序。

我的问题是测试结束后，如何以编程方式关闭Selenium2打开的每个浏览器窗口/选项卡？由于每次测试后每次关闭如此多的浏览器窗口/选项卡非常耗时。

我看到有一些选项可以在Java（Selenium2的本地语言）中做同样的事情（我也在使用.jar文件），但是在PHP中我找不到等效的选项。

有关更多信息，我包括了我正在尝试的代码。

我想写FeatureContext.php的example.feature关于此页面，那就是：

# features/search.feature
Feature: Search
    In order to see a word definition
    As a website user
    I need to be able to search for a word

    Scenario: Searching for a page that does exist
        Given I am on "/wiki/Main_Page"
        When I fill in "search" with "Behavior Driven Development"
        And I press "searchButton"
        Then I should see "agile software development"

    Scenario: Searching for a page that does NOT exist
        Given I am on "/wiki/Main_Page"
        When I fill in "search" with "Glory Driven Development"
        And I press "searchButton"
        Then I should see "Search results"

我FeatureContext.php的如下：

<?php

use Behat\Behat\Tester\Exception\PendingException;
use Behat\Behat\Context\Context;
use Behat\Behat\Context\SnippetAcceptingContext;
use Behat\Gherkin\Node\PyStringNode;
use Behat\Gherkin\Node\TableNode;

/**
* Defines application features from the specific context.
*/
class FeatureContext implements Context, SnippetAcceptingContext
{
    /**
    * Initializes context.
    *
    * Every scenario gets its own context instance.
    * You can also pass arbitrary arguments to the
    * context constructor through behat.yml.
    */
    public function __construct()
    {

        $this->driver = new \Behat\Mink\Driver\Selenium2Driver('firefox');
        $this->session = new \Behat\Mink\Session($this->driver);        
        $this->session->start();
    }


    /**
    * @Given I am on :url
    */
    public function iAmOn($url)
    {
        $this->session->visit('http://en.wikipedia.org'.$url);
    }

    /**
    * @When I fill in :field with :text
    */
    public function iFillInWith($field, $text)
    {
        $this
            ->session
            ->getPage()
            ->find('css', '[type=' . $field . ']')
            ->setValue($text);
    }

    /**
    * @When I press :button
    */
    public function iPress($button)
    {
        $this
            ->session
            ->getPage()
            ->find('css', '[id=' . $button . ']')
            ->press();
    }

    /**
    * @Then I should see :text
    */
    public function iShouldSee($text)
    {
        $title = $this
            ->session
            ->getPage()
            ->find('css', 'h1')
            ->getText();

        if ($title !== $text) {
            new Exception('Invalid page');
        }
        $this->driver->close();
    }
}