Re: any struts 2 unit testers out there?

Fri, 04 Apr 2008 14:05:36 -0700

As Ian says, the mock objects supplied by XWork may make this all a lot easier, but in any case all this is predicated on the fact that you're using ActionSupport's implementation of TextProvider which doesn't make provision for mocking at test time. I think it would make a great deal of sense to improve that (open an enhancement request in Jira), but in the mean time, there's nothing preventing you from providing a getText() implementation that's more conducive to testing.
I feel your pain on this one, and the right solution is to fix the framework (patches always welcome ;-), but it shouldn't be that hard to get around. 

L.

paulbrickell wrote:

Actually thats an interesting post. To my mind it doesn't demonstrate a
solution. It demonstrates the problem.

Here is why I think this.

Struts 2 is just frankly brilliant for people doing test first development.
The classes you create really are POJOs. There are no dependencies on any
framework in my action classes. For example parameters are parsed well away
from my action and the values are set using simple properties, things like
sessions are simply maps. It is a truly new world for those of who have
suffered the horror of mocking http requests, responses, context and the
like.

But this simple scenario brings all that pain flooding back. I add a line in
my action like this...

String yadaYada = getText("some.doodad");

And my lovely world comes unraveled real quick. Now I need mock objects up
the ying-yang.

I started using the tutorial from the link posted (I am an Arsenal fan btw,
so got two for the price of one, thanks), but it still doesn't provide a
simple solution to the problem. To get this to work I have to build not just
the application context but a mass of supporting objects to get a web
application framework up and running before I can test my simple POJO.

I am not going to give up just yet, but I think I am still going to have to
look for another way.

Cheers,
Paul B.





Relph,Brian wrote:


I recommend creating an action context.  Here is the basic guide I
followed to do so:


http://arsenalist.com/2007/06/18/unit-testing-struts-2-actions-spring-junit/ 


If you are not using spring or the struts2 spring plugin, you can cut out
all the code around the applicationContext.


-----Original Message-----

From: paulbrickell [mailto:[EMAIL PROTECTED] 
Sent: Thursday, April 03, 2008 11:44 AM

To: user@struts.apache.org
Subject: Re: any struts 2 unit testers out there?


I am trying to deal with the same issue. Did you get any resolution?

Following on from the reply asking for a stack trace, here is what I am
getting...


java.lang.NullPointerException
        at
com.opensymphony.xwork2.util.LocalizedTextUtil.findText(LocalizedTextUtil.java:299)
        at
com.opensymphony.xwork2.TextProviderSupport.getText(TextProviderSupport.java:172)
        at
com.opensymphony.xwork2.TextProviderSupport.getText(TextProviderSupport.java:87)
        at com.opensymphony.xwork2.ActionSupport.getText(ActionSupport.java:80)
        <SNIP>
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
        at
org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98)
        at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79)
        at
org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87)
        at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77)
        at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
        at
org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod(JUnit4ClassRunner.java:88)
        at
org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
        at
org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
        at
org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
        at
org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
        at
org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
        at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:38)
        at
org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
        at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
        at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
        at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
        at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)


It is caused by ActionContext.getContext() returning null. Quite obviously
I do not have an action context during my unit testing.

Now I can certainly use the ActionContext.setContext() in my tests setup
method to push one into thread local storage and that works OK. It isn't
ideal though because ActionContext is a concrete class and so my choices

then become a bit limited. 


I could create an instance but when I try this I find I have to create a
rather large object model to make it actually work. To the point where I
despair and give up.

Alternatively I could use a mock library (like easy mock). But I am not
inclined to include a mocking library that requires byte code rewriting
(not even for testing).

What I really want to do is inject a text provider into the ActionSupport
class. At the top of the ActionSupport class is this...

private final transient TextProvider textProvider = new
TextProviderFactory().createInstance(getClass(), this);


Damn its final and so I cannot inject my own text provider. 


BUT it uses a factory, thats good. I know I will have a look at the
factory I bet I can monkey with that and inject a mock. Nope. It's all
instance based. No way I can get in there. And thats that. Now what do I
do?

I can see two (half) workable solutions.

One is to override the the getText method in the action class when I
instantiate it during testing. So I end up doing this in all my action
unit tests...

        Action action = new MyAction()
        {
            @Override
            public String getText(String textName)
            {
                return "mocked";
            }
        };

It works, but its cheese.

Or two I can add a level of indirection in my action class, like so...


    String text =
MyTextProviderFactory.getInstance(class.name).getText("some.property");

Then I can use a delegate to the real text provider during live code and a
mock of my own text provider during testing. The question here is, Why for
the love of Pete, why?

So in conclusion there are at least four options for testing Action
classes that use get text.

1. Build an action context by hand. (Too hard) 2. Use a class rewriting
mocking library. (Not on my watch) 3. Mock the get text method. (Cheese)
4. Add another level of indirection. (Man thats just annoying)

Comments?

BTW If you got this far, thanks for taking the time.
Paul B.




Session Mwamufiya wrote:

Hi All,


Would someone let me know whether it's possible to tweak something so 
that JUnit test code can run on an action method that calls the 
ActionSupport method getText() to fetch string resources from a

package.properties file.

As it stands, I keep getting a null exception when getText() is called 
during the unit test.


Thanks,
Session


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