Mrunal Gosar Mrunal Gosar - 2 months ago 7
Java Question

static Webdriver instance synchronization in java

GlobalVariables class holds different variables which are used across my framework one of them is WebDriver instance:

public class GlobalVariables
{
public static WebDriver driver;
//Some other static global variables required across my framework
public GlobalVariables(String propertiesFile)
{
initializeVariables(propertiesFile);
}
public void initializeVariables(String propertiesFile)
{
GlobalInitializer obj=new GlobalInitializer();
obj.initialize(String propertiesFile);
}
}


GlobalInitializer contains methods to initialize all the GlobalVariables:

public class GlobalInitializer extends GlobalVariables
{
public void initialize(String propertiesFile)
{
//Some logic to read properties file and based on the properties set in it, call other initialization methods to set the global variables.
}
public void initializeDriverInstance(String Browser)
{
driver=new FireFoxDriver();
}


//Some other methods to initialize other global variables.
}

I have many GetElement classes which use the driver instance to get UI control elements E.g:

public class GetLabelElement extends GlobaleVariables
{
public static WebElement getLabel(String someID)
{
return driver.findElement(By.id(someId));
}
//Similar methods to get other types of label elements.
}

public class GetTextBoxElement extends GlobaleVariables
{
public static WebElement getTextBox(String someXpath)
{
return driver.findElement(By.xpath(someXpath));
}
//Similar methods to get other types of text box elements.
}


I have other classes which perform some actions on the UI Control(This classes too use the global variables) E.g:

public class GetLabelProperties extends GlobalVariables
{
public static String getLabelText(WebElement element)
{
return element.getText();
}
}

public class PerformAction extends GlobalVariables
{
public static void setText(String textBoxName,String someText)
{
driver.findElement(someLocator(textBoxName)).setText("someText");
}
//Some other methods which may or may not use the global variables to perform some action
}


My test class in testng looks like this:

public class TestClass
{
GlobalVariables globalObj=new GlobalVariables(String propertiesFile);
@Test(priority=0)
{
GlobalVariables.driver.get(someURL);
//Some assertion.
}
@Test(priority=1)
{
WebElement element=GetLabelElement.getLabel(someID);
String labelName=GetLabelProperties.getLabelText(element);
//Some assertion.
}
@Test(priority=2)
{
WebElement element=GetTextBoxElement.getTextBox(someXpath);
PerformAction.setText(element.getText(),someText);
//Some assertion.
}
}


I have similar multiple test classes based on scenarios.
Now this tests are running fine if i am running them individually. But when i try to run them in parallel, then this tests are failing in some weird fashion. On analyzing i found out that its the static global variables which are getting initialized by each tests thus leaving the other tests to fail. Now how should i go about achieving my objective to run multiple tests parallely with minimal changes in my framework design? i have tried searching for options, and i have come across some option i.e 1) use of synchronized. 2) Create ThreadLocal instance(Note : I have tried this solution but still same issue. tests are mixing up with each other resulting in failure. I had marked the WebDriver instance as ThreadLocal and overriden the initialValue method of ThreadLocal to initialize the driver instance. Still i am not sure whether i had implemented it correctly or not.). Now i am not sure how best to implement any one of this solution in the given scenario. Any help is appreciated. TIA!

Answer

I have found out the solution : Use of ThreadLocal is the best solution to run tests in a huge multithreaded environment. Code snippet to use WebDriver in multithreaded environment:

public static ThreadLocal<WebDriver> driver;
driver=new ThreadLocal<WebDriver>()
                {
                    @Override
                    protected WebDriver initialValue()
                    {
                        return new FirefoxDriver(); //You can use other driver based on your requirement.
                    }
                };

Now every time a test thread is created a new browser will open. ThreadLocal will make sure that there's only one copy of static webdriver instance per thread. [NOTE: Make sure your other global variables are too ThreadLocals. In my case they were not thats why i was running into test goof up issue]. Some extra knowledge which i would like to share so that others may find it informative. In ThreadLocal whenever the ThreadLocal.get() method is called you have to make sure that there is a provision to initialize the thread local as shown above in initialValue() method or you may run into null pointer exception. Thanks everyone.