How to execute concurrent tests with Selenium WebDriver on a single machine? - selenium

Question

My goal is to run multiple tests on a single machine in parallel. For that I'm using Selenium WebDriver with Firefox and Mbunit. Unfortunately it looks like like driver creation in Selenium is not thread safe and I have to wrap this part of the code with global lock. This is not the end of the world but my question is if this is all I need to do or maybe there are other parts that need synchronization? Another option would be to have AppDomain or Process isolation in MBUnit but I'm not sure if this is implemented.
[TestFixture]
[Parallelizable]
public class Class1
{
public static object padlock = new object();
[Test]
[Parallelizable]
public void Test1()
{
var driver = CreateDriver();
driver.Navigate().GoToUrl("http://www.mozilla.org");
driver.FindElementByCssSelector("a[href='/projects/']").Click();
Thread.Sleep(TimeSpan.FromSeconds(5));
driver.Quit();
}
[Test]
[Parallelizable]
public void Test3()
{
var driver = CreateDriver();
driver.Navigate().GoToUrl("http://www.mozilla.org");
driver.FindElementByCssSelector("a[href='/contribute/']").Click();
Thread.Sleep(TimeSpan.FromSeconds(5));
driver.Quit();
}
**private FirefoxDriver CreateDriver()
{
lock(padlock)
{
return new FirefoxDriver();
}
}**
}

Answer 1

I've been using MbUnit and Selenium in parallel, and I can assure you MbUnit is completely thread safe, and works perfectly once you instantiate WebDriver correctly. You should be fine with just the lock.
I would like to point out that using your code example your tests will not fail correctly. On any failed assertion or thrown exception you will not reach the Quit() section of your code. This is why the Setup/Teardown methods are typically used to start/stop the browser.
FYI, You can still use the setup/teardown methods in parallel, you just need a way of storing/referencing the Driver. You can use an IDictionary referenced by TestStep name.

Answer 2

I don't know how work MBunit, but there are differences between cocnurency and parallelism.
My opinion it's that an selenium test can be well integrated in concept of parallelism execution. Anyway, discution can be confusing.
So, how can be done.
1. Create an class that implements Runnable or extends Thread class. This class will launch test, something like this:
class MyClass implements Runnable
{
private Thread t;
public MyClass()
{
t=new Thread (this);
t.start();
}
#Override
public void run() {
WebDriver w = new FirefoxDriver();
// begin your test
}
}
In Main class, create multiple instance of MyClass. Each of them will launch an test into it's own thread.
Here it's link for Thread class documentation: http://docs.oracle.com/javase/1.3/docs/api/java/lang/Thread.html