How to unit testing (sub)module that uses DI?

[Dan King <da...@yahoo.com>]

Hi all,

I have a webapp (sub)module that uses Spring's dependency injection; how can/should I load the application context so I may run the unit tests for this module? 

Once all the modules are complete, I will add them to the webapp as "dependencies" and load the application context via the web container and Spring's "ContextLoaderListener."

-Dan



      


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Re: How to unit testing (sub)module that uses DI?

[Karl Heinz Marbaise <ka...@soebes.de>]

Hi,

that sound not like a Unit Test more like an integration test...which can be
done by using cargo plugin...there you can startup e.g. Tomcat and run
Integration test on the deployed system...

On the other hand if you have only DI's than you only need an
applicationContext.xml setup for the Unit Tests to do the unit tests if this
would fit your needs...But i'm not sure about that...

Kind regards
Karl Heinz Marbaise
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Re: How to unit testing (sub)module that uses DI?

[Wes Wannemacher <we...@wantii.com>]

There are two ways I usually solve this problem. The choice between
the two (for me) is usually a matter of how deep I want the testing to
go.

In many cases, I use spring injection from my unit tests by combining
JUnit's @RunWith annotation and some Spring Annotations. Here is an
example -

    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations =
{"classpath*:applicationContext-test.xml"})
    public class StockInfoManagerTest {
	
	    @Autowired
	    @Qualifier("stockInfoDao")
	    private GenericDao<CDOV_StockInfo,String> stockInfoDao;

This is mostly self-explanatory... However, I will mention that I
usually don't point to the same applicationContext.xml file that I
would use for production. In this case, I configure spring to
instantiate and talk to an hsqldb database. Then I can push stuff in
and then pull it back out to ensure that database operations complete
successfully.

In many other cases, I prefer a "mocking" approach. Here is an example -

    @Test
    public void executeTest() throws Exception {
        // setup the mock object
        final StockInfoManager stockInfoManager =
context.mock(StockInfoManager.class);

        // create expectations for mock object's execution
        context.checking(new Expectations() {{
            oneOf(stockInfoManager).getAll(); will(returnValue(new
ArrayList<CDOV_StockInfo>()));
        }});

What mocking does is create a proxy that records requested operations
and behaves the way you describe it. The advantage of mocking is that
you don't have to worry about fully populating dependencies, etc. If I
feel like the implementations that get wired in at production have
already been properly tested, then I will use mocking to test.

In my case, typically, I will fully test services by wiring them with
Spring and having them hit a test database (usually embedded like
hsqldb or derby). Then, once I am confident that the services do what
they advertise, I will unit test the user interface actions (Struts 2
actions, in my case), but injecting mocked services and work on making
sure that the actions operate the way I intend (by setting the mock's
expectations then interacting with the action the way I expect the
framework to call them).

Of course, this is really somewhat outside of the scope of a
maven-users list... If you want to get into the theory of good unit
testing, I think there are a few good books out there. Otherwise, just
get familiar with at least these two techniques and try to
consistently apply a set of practices that best tests your code (as
opposed to attempting to test each and every element of your
application's setup).

-Wes

On Mon, May 3, 2010 at 9:15 AM, Dan King <da...@yahoo.com> wrote:
> Hi all,
>
> I have a webapp (sub)module that uses Spring's dependency injection; how can/should I load the application context so I may run the unit tests for this module?
>
> Once all the modules are complete, I will add them to the webapp as "dependencies" and load the application context via the web container and Spring's "ContextLoaderListener."
>
> -Dan
>
>
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
> For additional commands, e-mail: users-help@maven.apache.org
>
>



-- 
Wes Wannemacher

Head Engineer, WanTii, Inc.
Need Training? Struts, Spring, Maven, Tomcat...
Ask me for a quote!

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