如何在 selenium 中并行运行多个类

Question

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Suite" thread-count="4" parallel="tests"  preserve-order="true">
    <test name="Login - firefox">
        <parameter name="browserName" value="firefox"></parameter>
        <classes>
            <class name="com.qa.logintests.LoginTest" />
            <class name="com.qa.logouttest.LogoutTest" />
        </classes>
    </test>

    <test name="Login - chrome">
        <parameter name="browserName" value="chrome"></parameter>
        <classes>
            <class name="com.qa.logintests.LoginTest" />
            <class name="com.qa.logouttest.LogoutTest" />
        </classes>
    </test>
</suite> 

1. Need to run multiple classes in parallel, if I run with only 1 browser with parallel = none then the code works fine.
2. But If I use parallel = tests and try to run, then for second class named as "LogoutTest", I am facing null pointer exception.
3. Can anyone suggest me how to resolve this issue?

Answer 1

As we want classes to be executed in parallel, we have to add parallel="classes" in the attribute of suite tag.

Replace parallel="tests" with parallel="classes"

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Suite" thread-count="4" parallel="classes">
    <test name="Login - firefox">
        <parameter name="browserName" value="firefox"></parameter>
        <classes>
            <class name="com.qa.logintests.LoginTest" />
            <class name="com.qa.logouttest.LogoutTest" />
        </classes>
    </test>

    <test name="Login - chrome">
        <parameter name="browserName" value="chrome"></parameter>
        <classes>
            <class name="com.qa.logintests.LoginTest" />
            <class name="com.qa.logouttest.LogoutTest" />
        </classes>
    </test>
</suite> 

Note: If one class is dependent to other for example, logout is dependent to login, then it obvious that it will throw null pointer exception. And it wouldn't be wise to run dependent things in parallel.