TestNG.xml

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

<suite name="oTTo TestSuite" allow-return-values="true" thread-count="4" parallel="tests" verbose="1">

    <listeners>
        <listener class-name="base.InvokedMethodListener"></listener>
    </listeners>

    <test name="Chrome run" thread-count="1">
        <parameter name="browser" value="chrome" />
        <classes>
            <class name="Tests" />
        </classes>
    </test>

    <test name="Firefox run" thread-count="1">
        <parameter name="browser" value="firefox" />
        <classes>
            <class name="Tests" />
        </classes>
    </test>

    <test name="Edge run" thread-count="1">
        <parameter name="browser" value="edge" />
        <classes>
            <class name="Tests" />
        </classes>
    </test>

    <test name="Internet Explorer run" thread-count="1">
        <parameter name="browser" value="IE" />
        <classes>
            <class name="Tests" />
        </classes>
    </test>

</suite>