Tutorial 32 – Run Parallel Selenium Tests In Chrome Browser using Docker Compose
Please read the previous article before reading this one.
In this article, we will learn how to run selenium tests in parallel against multiple docker containers.
Let us cd to directory where we have placed .yml file
Start docker engine by double clicking docker desktop icon
Wait for the docker engine to start, the below command shows that no containers are running at present
We still have 4 docker images in our local
Let us create 2 chrome containers
docker-compose up --scale chrome=2 -d
Notice below that 2 chrome containers are created
Also make sure that 2 chrome containers are running by executing below command
Launch http://localhost:4444
Notice below that 2 chrome browsers are running
Let us create 2 TestNG classes (Test1.java and Test2.java) as shown below
Next, we will create testng.xml file to enable us to run our tests in parallel.
To create testng.xml, right click project > TestNG > Convert to TestNG
Click Next and click Finish, the testng.xml gets created as shown below
Replace the default contents of testng.xml with below content and save it. Notice that both the tests are pointing to Test1.java (this means that the 2 chrome sessions would execute the same Test1.java)
Note: Sometimes when we specify thread count, the test might not run properly, that’s why haven’t used thread count in the above xml.
Execute the testng.xml
Notice below that 2 concurrent (2 parallel tests) chrome sessions are started, shown by 
Notice below 2 chrome session running
Notice below that the 2 Tests pass
Let us now point the second test to Test2.java (this means that one chrome session would execute Test1.java and another chrome session would execute Test2.java)
Save the xml
Execute the testng.xml
Notice below that 2 concurrent (2 parallel tests) chrome sessions are started, shown by
That is how we can execute our tests in parallel using docker compose.
Snapshot (testng xml to execute Test1 in 2 parallel chrome sessions)
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd" >
<suite name="suite" parallel="tests">
<test name="Chrome1">
<classes>
<class name="sel4scripts.Test1" />
</classes>
</test>
<test name="Chrome2">
<classes>
<class name="sel4scripts.Test1" />
</classes>
</test>
</suite>
Snapshot (testng xml to execute Test1 and Test2 in 2 parallel chrome sessions)
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd" >
<suite name="suite" parallel="tests">
<test name="Chrome1">
<classes>
<class name="sel4scripts.Test1" />
</classes>
</test>
<test name="Chrome2">
<classes>
<class name="sel4scripts.Test2" />
</classes>
</test>
</suite>
Code snippet (Test1.java for chrome browser)
package sel4scripts;
import java.net.MalformedURLException;
import java.net.URL;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.testng.annotations.Test;
public class Test1 {
@Test
public void TestParallel() throws MalformedURLException, InterruptedException
{
ChromeOptions opt = new ChromeOptions();
WebDriver driver = new RemoteWebDriver(new URL("https://localhost:4444"),opt);
driver.get("http://google.com");
driver.findElement(By.name("q")).sendKeys("Learning Standalone grid");
System.out.println("Test executed successfully");
}
}
Code snippet (Test2.java for chrome browser)
package sel4scripts;
import java.net.MalformedURLException;
import java.net.URL;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.testng.annotations.Test;
public class Test2 {
@Test
public void grid2() throws MalformedURLException, InterruptedException
{
ChromeOptions opt = new ChromeOptions();
WebDriver driver = new RemoteWebDriver(new URL("https://localhost:4444"),opt);
driver.get("http://google.com");
driver.findElement(By.name("q")).sendKeys("Learning Standalone grid");
System.out.println("Test executed successfully");
}
}
Thank you for reading!