Question

I want to group the common methods in one file and use it. For example, login to a page using selenium may be used in multiple times. Define that in class A and call it in class B. However, it throws null pointer exception.

class A has

public void test_Login() throws Exception
    {
        try{
        selenium.setTimeout("60000");
        selenium.open("http://localhost");
        selenium.windowFocus();
        selenium.windowMaximize();
        selenium.windowFocus();
        selenium.type("userName", "admin");
        selenium.type("password", "admin");
        Result=selenium.isElementPresent("//input[@type='image']");
        selenium.click("//input[@type='image']");
        selenium.waitForPageToLoad(Timeout);
        }
        catch(Exception ex)
        {   
            System.out.println(ex);
            ex.printStackTrace();
        }
    }

with all other java syntax

in class B

public void test_kk() throws Exception
    {

        try
        {
            a.test_Login();
        }
        catch(Exception ex)
        {
            System.out.println(ex);
            ex.printStackTrace();
        }
    }

with all syntax.

When I execute class B, I got this error,

java.lang.NullPointerException
        at A.test_Login(A.java:32)
        at B.test_kk(savefile.java:58)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at junit.framework.TestCase.runTest(TestCase.java:168)
        at junit.framework.TestCase.runBare(TestCase.java:134)
        at com.thoughtworks.selenium.SeleneseTestCase.runBare(SeleneseTestCase.j
ava:212)
        at junit.framework.TestResult$1.protect(TestResult.java:110)
        at junit.framework.TestResult.runProtected(TestResult.java:128)
        at junit.framework.TestResult.run(TestResult.java:113)
        at junit.framework.TestCase.run(TestCase.java:124)
        at junit.framework.TestSuite.runTest(TestSuite.java:232)
        at junit.framework.TestSuite.run(TestSuite.java:227)
        at junit.textui.TestRunner.doRun(TestRunner.java:116)
        at junit.textui.TestRunner.doRun(TestRunner.java:109)
        at junit.textui.TestRunner.run(TestRunner.java:77)
        at B.main(B.java:77)

I hope someone must have tried this before. I may miss something here.

Answer 1

The way we do it is, we have helper classes with static methods on them. In the actual test cases we set up our selenium object and pass the object into the static method so it can operate on it.

public BaseHelper
{
    public static login( final String username, final String password, final DefaultSelenium selenium )
    {
     selenium.type("userName", username);
     selenium.type("password", password);
     selenium.click("loginbutton");
    }
}


public LoginTest
{
    DefaultSelenium selenium;

    onSetup()
    {
      selenium = new DefaultSelenium(...);
    }  

    public testLogin()
    {
      BaseHelper.login( "admin", "admin", selenium);
      // assert that this passed
      BaseHelper.login( "foo", "bar", selenium);
      // assert this failed because no user 'foo'
      BaseHelper.login( "admin", "bar", selenium);
      // assert this failed because admin's password was incorrect
    }
}

Hope this illustrates the point.

Besides the better readability and easier maintenance, you are also able to test multiuser behavior by creating two (or more) selenium objects and pass those around in the tests.