Integration Test using mocked beans

[sandeep-chekuri]

We have a following scenario,
OurServiceApplication is adding the below bundle during the initialize(Bootstrap...)
GuiceBundle guiceBundle = GuiceBundle.newBuilder()
.addModule(new OurModule())...

OurModule has the bean injection of DatabaseSource etc.

We are writing the integration test as below
DropwizardAppRule RULE = new DropwizardAppRule<>(
OurServiceApplication.class, "our.yml")

Now we want to inject in-memory datasource, can u pls let us know how to inject it?
Please note that TestModule has the InMemoryDatasource beans..

[heldeen]

The way I did it at a couple of companies that has worked fairly well is extend io.dropwizard.testing.DropwizardTestSupport so you can override com.alianza.dropwizard.testing.AlzDropwizardTestSupport#newApplication. The new DropwizardTestSupport should take your TestModule and use that and your Dropwizard Application to spin up the server. Here's a couple of snippets:

public class Main extends Application<BasicExampleConfig> {

    private final Module appModule;

    public Main() {
        appModule = new BasicExampleModule();//Guice module used for normal runtime
    }

    @VisibleForTesting
    public Main(Module... overrideModules) {
        appModule = Modules.override(new BasicExampleModule()).with(overrideModules);
    }

    public static void main(String... args) throws Exception {
        new Main().run(args);
    }

    @Override
    public String getName() {
        return "basic-example";
    }

    @Override
    public void initialize(final Bootstrap<BasicExampleConfig> bootstrap) {
        super.initialize(bootstrap);
        GuiceBundle<BasicExampleConfig> bundle = GuiceBundle.newBuilder()
                .addModule(appModule)
                //other GuiceBundle builder options
                .build();
        bootstrap.addBundle(bundle);
    }
    //other methods omitted
}

public class YourDropwizardTestSupport<C extends Configuration> extends DropwizardTestSupport {

    private final Module externalMocksModule;

    public YourDropwizardTestSupport(Class<? extends Application<C>> applicationClass, @Nullable String configPath, Module externalMocksModule) {
        super(applicationClass, configPath);
        this.externalMocksModule = requireNonNull(externalMocksModule);
    }

    @Override
    public Application<C> newApplication() {
        try {
            //this is way fancier than you need but it finds the constructor in the Application class that takes a Guice Module and uses that to spin up your server for integratoin tests
            return (Application<C>) applicationClass.getConstructor(Module[].class).newInstance(new Object[]{new Module[] {externalMocksModule}});
        } catch (Exception e) {
            throw propagate(e);
        }
    }
}