Run selenium test scripts in multiple browsers using NUnit Framework

[TestFixture(typeof(InternetExplorerDriver))]
[TestFixture(typeof(FirefoxDriver))]
public class testwithMultipleBrowsers<Testwebdriver> where Testwebdriver:IWebDriver ,new()
{
 IWebDriver driver;
 [SetUp]
 public void testsetup()
   {
    driver = new Testwebdriver(); 
    }
 [TearDown]
 public void teardownTest()
 {
  driver.Quit();
  }
  [Test]
  public void testMulitBrowser()
 {
  driver.Navigate().GoToUrl("http://google.co.in");
  driver.FindElement(By.Name("q")).SendKeys("testingtools");
  driver.FindElement(By.Name("btnG")).Click();
  }
}