Configure parallel execution of tests and classes in testng.xml

Question

My testng.xml is as given below:

<suite name="Automation Suite" allow-return-values="true" verbose="1" parallel="tests" thread-count="2">
    <test name="Login Test cases 01">
        <parameter name="Operating_System" value="Windows 8"/>
        <parameter name="Browser_Name" value="Internet Explorer"/>
        <parameter name="Browser_Version" value="11"/>
        <parameter name="Base_URL" value="https://www.google.com"/>
        <classes>
            <class name="com.automation.tool.Automation_01"/>
            <class name="com.automation.tool.Automation_02"/>
        </classes>
    </test>
    <test name="Login Test cases 02">
        <parameter name="Operating_System" value="Windows XP"/>
        <parameter name="Browser_Name" value="Mozilla Firefox"/>
        <parameter name="Browser_Version" value="27"/>
        <parameter name="Base_URL" value="https://www.google.com"/>
        <classes>
            <class name="com.automation.tool.Automation_01"/>
            <class name="com.automation.tool.Automation_02"/>
        </classes>
    </test>
</suite>

Currently the tests are getting executed in parallel. But I wish to execute the classes also in parallel as below:

Thread 01 : Test 01 Class 01
Thread 02 : Test 01 Class 02
Thread 03 : Test 02 Class 01
Thread 04 : Test 02 Class 02

Please let me know, how to configure this setup.

Answer 1

Got it now...

<suite name="Automation Suite" allow-return-values="true" verbose="1" parallel="tests" thread-count="2">
    <test name="Login Test cases 01" parallel="classes" thread-count="2">
        <parameter name="Operating_System" value="Windows 8"/>
        <parameter name="Browser_Name" value="Internet Explorer"/>
        <parameter name="Browser_Version" value="11"/>
        <parameter name="Base_URL" value="https://www.google.com"/>
        <classes>
            <class name="com.automation.tool.Automation_01"/>
            <class name="com.automation.tool.Automation_02"/>
        </classes>
    </test>
    <test name="Login Test cases 02" parallel="classes" thread-count="2">
        <parameter name="Operating_System" value="Windows XP"/>
        <parameter name="Browser_Name" value="Mozilla Firefox"/>
        <parameter name="Browser_Version" value="27"/>
        <parameter name="Base_URL" value="https://www.google.com"/>
        <classes>
            <class name="com.automation.tool.Automation_01"/>
            <class name="com.automation.tool.Automation_02"/>
        </classes>
    </test>
</suite>

Answer 2

In suite tag change the "parallel" attribute value from "tests" to "classes" for example:

If you wish to execute

1. tests in parallel then use = parallel="tests"
2. classes in parallel then use = parallel="classes"
3. Methods in parallel then use = parallel="methods"