Selenium Grid2 : parallel tests run on the same browser at the same time

Question

I've got two nodes with same configurations(Win7, ie9). I set testNG to execute two tests one each node at the same time. Selenium Grid does open two browsers(one each node) at the same time, but the tests seem to be executed in just one browser -- the username is typed in in the same browser twice. And if I set thread-count=1, both tests succeed.

The testNG test suite xml file:

<suite name="ExampleTest" parallel="tests" thread-count="2"> 
    <test name="ExampleTest1">
        <classes>
            <class name="com.mycompany.testsuites.GridTest">
                <methods>
                    <include name="test1"></include>
                </methods>
            </class>
        </classes>
    </test>
    <test name="ExampleTest2">
        <classes>
            <class name="com.mycompany.testsuites.GridTest">
                <methods>
                    <include name="test2"></include>
                </methods>
            </class>
        </classes>
    </test>

The test class GridTest :

public class GridTest {

    private WebDriver driver;
    String hubUrl = "http://12.11.14.15:4444/wd/hub";

    @BeforeClass
    public void beforeClass() throws MalformedURLException {
        DesiredCapabilities capability = DesiredCapabilities.internetExplorer();
        driver = new RemoteWebDriver(new URL(hubUrl), capability);
        Page.setUp(driver);  //Page is the base class of all page objects.
                             //The static setUp method assign a WebDriver object 
                             //to static Page.driver, which shared by all pages.
    }

    @AfterClass
    public void afterClass() {
        driver.quit();
    }

    @Test
    public void test1() {
        driver.get("http://12.11.15.16");
        LoginPage login = new LoginPage();
        login.setUp();                  // set up the Login Page
        login.txtUsername().clear();    //clear the username input box
        login.txtUsername().sendKeys("username");    // input user name
        // ...
    }

    @Test
    public void test2() {
        driver.get("http://12.11.15.16");
        LoginPage login = new LoginPage();
        login.setUp();
        login.txtUsername().clear();
        login.txtUsername().sendKeys("username");
        // ...
    }
}

I use selenium-server-standalone-2.41.0.jar for the hub and nodes.

Robbie Wareham Robbie Wareham · Accepted Answer · 2014-04-23T05:50:06

The behaviour you are seeing is correct.

The driver is created in @beforeClass and this is only executed once, therefore only one browser is created which is used by both tests concurrently.

If you were to change to @beforeMethod, then a browser would be created per test BUT this would still fail as the same variable (driver) is being used to store the driver instance. You would see two browsers open but both tests executing in the second.

To run parallel at a test level then you need to ensure each test is entirely encapsulated such as creating its own driver within its own context, and this would not allow you use set up and tear down.

Usually I would always run parallel at class level, as this approach allows you to still use set up and tear down to create the driver instance. I would recommend changing your XML to run parallel=classes. Obviously you have to have multiple classes but I assume in reality you have more then two tests to run!

Selenium Grid2 : parallel tests run on the same browser at the same time

3 Answers