Unit testing a Restlet extractor

Question

I'm looking for some guidance on real unit testing for Restlet components, and specifically extractors. There is plenty of advice on running JUnit to rest entire endpoints, but being picky this is not unit testing, but integration testing. I really don't want to have set up an entire routing system and Spring just to check an extractor against a mock data repository.

The extractor looks like this:

public class CaseQueryExtractor extends Extractor {

    protected int beforeHandle(Request request, Response response) {
        extractFromQuery("offset", "offset", true);
        extractFromQuery("limit", "limit", true);

        // Stuff happens...

        attributes.put("query", query);
        return CONTINUE;
    }
}

I'm thinking part of the virtue of Restlets is that its nice routing model ought to make unit testing easy, but I can't figure out what I need to do to actually exercise extractFromQuery and its friends, and all my logic that builds a query object, without mocking so much that I'm losing testing against a realistic web request.

And yes, I am using Spring, but I don't want to have to set the whole context for this -- I'm not integration testing as I haven't actually finished the app yet. I'm happy to inject manually, once I know what I need to make to get this method called.

Here's where I'm at now:

public class CaseQueryExtractorTest {

    private class TraceRestlet extends Restlet {
        // Does snothing, but prevents warning shouts
    }

    private CaseQueryExtractor extractor;

    @Before
    public void initialize() {

        Restlet mock = new TraceRestlet();
        extractor = new CaseQueryExtractor();
        extractor.setNext(mock);
    }

    @Test
    public void testBasicExtraction() {

         Reference reference = new Reference();
         reference.addQueryParameter("offset", "5");
         reference.addQueryParameter("limit", "3");
         Request request = new Request(Method.GET, reference);
         Response response = extractor.handle(request);
         extractor.handle(request, response);

         CaseQuery query = (CaseQuery) request.getAttributes().get("query");
         assertNotNull(query);
     }
}

Which of course fails, as whatever set up I am doing isn't enough to make Restlets able to extract the query parameters.

Any thoughts or pointers?

Answer 1

There is a test module in Restlet that can provide you some hints about unit testing. See https://github.com/restlet/restlet-framework-java/tree/master/modules/org.restlet.test/src/org/restlet/test.

You can have a look at class HeaderTestCase (see https://github.com/restlet/restlet-framework-java/blob/master/modules/org.restlet.test/src/org/restlet/test/HeaderTestCase.java).

For information, if you use attributes from request, your unit test will pass ;-) See below:

public class CaseQueryExtractor extends Extractor {

    protected int beforeHandle(Request request, Response response) {
        extractFromQuery("offset", "offset", true);
        extractFromQuery("limit", "limit", true);

        // Stuff happens...

        CaseQuery query = new CaseQuery();

        Map<String,Object> attributes = request.getAttributes();
        attributes.put("query", query);
        return CONTINUE;
    }
}

I don't know if you want to go further...

Hope it helps you, Thierry