How to Limiting the Number of Parallel Tests with ThreadCount in TestNG?

TestNG supports multi?threading i.e. a @Test methods can be invoked parallelly. A test or multiple test methods can be invoked from multiple threads. Therefore, multiVthread is useful if @Test methods need to be run asynchronously in parallel.

Multi?threading can be achieved by using keyword ? thread?count =<integer> at Testng.xml. Thread count is basically number of instances running to execute multiple tests simultaneously or parallelly. The attribute thread?count allows the user to specify how many threads should be run for this execution.

In this example, 5 @Test method will execute in parallel from 5 threads.

In this article, we will illustrate how to achieve multithreading.

Approach/Algorithm to Solve this Problem

• Step 1: Create a TestNG class ? NewTestngClass.

• Step 2: Write 5 @Test methods in the class ? NewTestngClass as shown in programming code section.

• Step 3: Now create the testNG.xml as given below to run the TestNG classes. Add thread?ount and parallel keyword.

• Step 4: Now, run the testNG.xml or directly testNG class in IDE or compile and run it using command line.

• In the output, user can see total 5 threads are running in parallel ? ID 18 to 22.

Example

The following code for common TestNG class ? NewTestngClass:

src/ NewTestngClass.java

import org.testng.ITestContext;
import org.testng.annotations.*;

public class NewTestngClass {

    @Test()
    public void testcase1(ITestContext testContext){
        System.out.println("Thread ID: "+Thread.currentThread().getId());
        int currentCount = testContext.getAllTestMethods()[0].getCurrentInvocationCount();
        System.out.println("Executing count: " + currentCount);
    }
    @Test()
    public void testcase2(ITestContext testContext){
        System.out.println("Thread ID: "+Thread.currentThread().getId());
        int currentCount = testContext.getAllTestMethods()[1].getCurrentInvocationCount();
        System.out.println("Executing count: " + currentCount);
    }
    @Test()
    public void testcase3(ITestContext testContext){
        System.out.println("Thread ID: "+Thread.currentThread().getId());
        int currentCount = testContext.getAllTestMethods()[2].getCurrentInvocationCount();
        System.out.println("Executing count: " + currentCount);
    }
    @Test()
    public void testcase4(ITestContext testContext){
        System.out.println("Thread ID: "+Thread.currentThread().getId());
        int currentCount = testContext.getAllTestMethods()[3].getCurrentInvocationCount();
        System.out.println("Executing count: " + currentCount);
    }
    @Test()
    public void testcase5(ITestContext testContext){
        System.out.println("Thread ID: "+Thread.currentThread().getId());
        int currentCount = testContext.getAllTestMethods()[4].getCurrentInvocationCount();
        System.out.println("Executing count: " + currentCount);
    }
} 

testng.xml

This is a configuration file that is used to organize and run the TestNG test cases.

It is very handy when limited tests are needed to execute rather than full suite.

<?xml version = "1.0" encoding = "UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >

<suite name = "Suite1" thread-count="5" parallel="methods">
   <test name = "test1">
      <classes>
    <class name = "NewTestngClass"/>
      </classes>
   </test>
</suite>

Output

Thread ID: 18
Thread ID: 22
Thread ID: 19
Executing count: 0
Thread ID: 20
Executing count: 0
Thread ID: 21
Executing count: 0
Executing count: 0
Executing count: 0

===============================================
Suite1
Total tests run: 5, Passes: 5, Failures: 0, Skips: 0
===============================================