title: Selenium browser starting twice when using a custom attribute for an Xunit test
body: <p>Created a custom attribute so that I can run different browsers without duplicating the test but when I run the test a browser opens before the test starts and then again when the test begins. Why is this happening?</p>
  
  <p>When I remove the code that starts the webdriver, then no browser start.
  When the webdriver is created in the test class then it works fine.</p>
  
  <p>The test method</p>
  
  <pre class="lang-cs prettyprint-override"><code>[Theory]
  [Browser("Chrome")]
  public void TestName(IWebDriver driver)
  {
     driver.Navigate().GoToUrl(_baseUrl);
  }
  </code></pre>
  
  <p>The custom attribute</p>
  
  <pre class="lang-cs prettyprint-override"><code>public class BrowserAttribute : DataAttribute
  {
      string _browser;
      IWebDriver _driver;
  
      public BrowserAttribute(string browser)
      {
          _browser = browser;
          _driver = new ChromeDriver(@"some path");
      }
  
      public override IEnumerable&lt;object[]&gt; GetData(MethodInfo testMethod)
      {
          return new List&lt;IWebDriver[]&gt; { new[] { _driver } };
      }
  }
  </code></pre>
  
  <p>I'm expecting only one browser to open but am getting two.</p>