Run Selenium tests in parallel with NUnit

MultiSeleniumTest.cs

[TestFixture(typeof(FirefoxOptions))]
[TestFixture(typeof(ChromeOptions))]
[Parallelizable(ParallelScope.All)]
public class MultiSeleniumTest<TOptions> where TOptions : DriverOptions, new()
{
    [ThreadStatic]
    private static IWebDriver driver;

    [SetUp]
    public void Setup()
    {
        var options = new TOptions();
        driver = new RemoteWebDriver(
            new Uri("http://localhost:4444/wd/hub"), options);
    }

    [Test]
    public void Test_NakovCom_Title()
    {
        driver.Navigate().GoToUrl("https://nakov.com");
        Assert.That(driver.Title.Contains("Svetlin Nakov"));
    }

    [Test]
    public void Test_Wikipedia_Title()
    {
        driver.Navigate().GoToUrl("https://wikipedia.org");
        Assert.That(driver.Title.Contains("Wikipedia"));
    }

    [Test]
    public void Test_Google_Title()
    {
        driver.Navigate().GoToUrl("https://google.com");
        Assert.That(driver.Title.Contains("Google"));
    }

    [TearDown]
    public void Shutdown()
    {
        driver.Quit();
    }
}

This example will run 6 Web browsers in parallel to execute 6 tests concurrently:

• 3 Chrome instances
• 3 Firefox instances

Create a separate IWebDriver instance before each test in [SetUp] and release it in [TearDown].

Define the driver as [ThreadStatic] + static to get a separate instance for each test execution.