Project Setup:

Gradle + basic Helo World

src/main/java/cavecomm/MainVerticle.java

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+package cavecomm;
+
+import io.vertx.core.AbstractVerticle;
+import io.vertx.core.MultiMap;
+import io.vertx.core.json.JsonObject;
+import io.vertx.ext.web.Router;
+
+public class MainVerticle extends AbstractVerticle {
+	  @Override
+	  public void start() throws Exception {
+	    // Create a Router
+	    Router router = Router.router(vertx);
+
+	    // Mount the handler for all incoming requests at every path and HTTP method
+	    router.route().handler(context -> {
+	      // Get the address of the request
+	      String address = context.request().connection().remoteAddress().toString();
+	      // Get the query parameter "name"
+	      MultiMap queryParams = context.queryParams();
+	      String name = queryParams.contains("name") ? queryParams.get("name") : "unknown";
+	      // Write a json response
+	      context.json(
+	        new JsonObject()
+	          .put("cavecomm", name)
+	          .put("address", address)
+	          .put("message", "Hello World")
+	      );
+	    });
+
+	    // Create the HTTP server
+	    vertx.createHttpServer()
+	      // Handle every request using the router
+	      .requestHandler(router)
+	      // Start listening
+	      .listen(8888)
+	      // Print the port
+	      .onSuccess(server ->
+	        System.out.println(
+	          "HTTP server started on port " + server.actualPort()
+	        )
+	      );
+	  }
+	}

src/test/java/cavecomm/TestMainVerticle.java

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+package cavecomm;
+
+import io.vertx.core.Vertx;
+import io.vertx.ext.unit.Async;
+import io.vertx.ext.unit.TestContext;
+import io.vertx.ext.unit.junit.RunTestOnContext;
+import io.vertx.ext.unit.junit.VertxUnitRunner;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(VertxUnitRunner.class)
+public class TestMainVerticle {
+
+  @Rule
+  public RunTestOnContext rule = new RunTestOnContext();
+
+  @Before
+  public void deploy_verticle(TestContext testContext) {
+    Vertx vertx = rule.vertx();
+    vertx.deployVerticle(new MainVerticle(), testContext.asyncAssertSuccess());
+  }
+
+  @Test
+  public void verticle_deployed(TestContext testContext) throws Throwable {
+    Async async = testContext.async();
+    async.complete();
+  }
+}