New annotation to generate a test http client interface for a Controller

[rbygrave]

Say we have a controller like below, and we want to test that controller:

@Controller
@Path("/ping")
class PingController {

    @Produces("text/plain")
    @Get
    String ping() {
          return Instant.now().toString();
    }
}

In a test, we specify that we desire a http client interface generated for this controller like say:

@GenerateHttpClient(controller=PingController.class, clientPattern="{}ClientApi")

... and that that generates a http client interface in test generated source like:

@Client
@Path("/ping")
interface PingClientApi {

    @Get
    HttpResponse<String> ping();
}

Note that the response types on the client interface should probably use HttpResponse so that the tests can access the response statusCode and response headers. So return HttpResponse<String> rather than String etc.

We can now inject the PingClientApi in a test like:

@InjectTest 
class MyPingControllerTest {

  @Inject PingClientApi pingClientApi;

    @Test
  void ping() {
        HttpResponse<String> res = pingClientApi.ping();

        assertThat(res.statusCode()).isEqualTo(200);
        assertThat(res.body()).isNotEmpty();
  }

}

What do we think about this idea?

[SentryMan]

How about we skip the annotation and automatically generate a test client interface during test compilation. (When http client is on the class path of course)

[rbygrave]

skip the annotation and automatically generate a test client interface

That makes sense to me. There should be no harm in doing that even when it isn't potentially used so yeah makes good sense I think. I like it.

[SentryMan]

what should be done about controllers like:

@Controller("/ping")
class PingController {

    @Post
    String ping(Context ctx) {
        //something
    }
}

[rbygrave]

That's a POST with an arbitrary/unknown body type. I think the body on the client side should be a HttpRequest.BodyPublisher.

[SentryMan]

POST is easy to solve, I'm talking about handling Jex/Javalin Context or the helidon ServerRequest/ServerResponse

[SentryMan]

Hmm, now that I think about it, it may not be a big deal