diff --git a/okapi-test-auth-module/src/main/java/org/folio/okapi/auth/MainVerticle.java b/okapi-test-auth-module/src/main/java/org/folio/okapi/auth/MainVerticle.java
index bd84dafe0..d453e9b16 100644
--- a/okapi-test-auth-module/src/main/java/org/folio/okapi/auth/MainVerticle.java
+++ b/okapi-test-auth-module/src/main/java/org/folio/okapi/auth/MainVerticle.java
@@ -1,11 +1,10 @@
 package org.folio.okapi.auth;
 
-import io.vertx.core.AbstractVerticle;
-import io.vertx.core.Promise;
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
 import io.vertx.core.Vertx;
 import io.vertx.ext.web.Router;
 import io.vertx.ext.web.handler.BodyHandler;
-import java.io.IOException;
 import java.lang.management.ManagementFactory;
 import org.apache.logging.log4j.Logger;
 import org.folio.okapi.common.OkapiLogger;
@@ -22,7 +21,7 @@
  */
 @java.lang.SuppressWarnings({"squid:S1192"})
 
-public class MainVerticle extends AbstractVerticle {
+public class MainVerticle extends VerticleBase {
 
   private final Logger logger = OkapiLogger.get();
 
@@ -40,7 +39,7 @@ public static void main(String[] args) {
   }
 
   @Override
-  public void start(Promise<Void> promise) throws IOException {
+  public Future<?> start() {
     Router router = Router.router(vertx);
     Auth auth = new Auth();
 
@@ -57,9 +56,9 @@ public void start(Promise<Void> promise) throws IOException {
     router.post("/_/tenant").handler(auth::tenantOp);
     router.route("/*").handler(auth::filter);
 
-    vertx.createHttpServer()
+    return vertx.createHttpServer()
         .requestHandler(router)
-        .listen(port).onComplete(result -> promise.handle(result.mapEmpty()));
+        .listen(port);
   }
 
 }
diff --git a/okapi-test-header-module/src/main/java/org/folio/okapi/header/MainVerticle.java b/okapi-test-header-module/src/main/java/org/folio/okapi/header/MainVerticle.java
index c756da2af..34cc59d84 100644
--- a/okapi-test-header-module/src/main/java/org/folio/okapi/header/MainVerticle.java
+++ b/okapi-test-header-module/src/main/java/org/folio/okapi/header/MainVerticle.java
@@ -1,7 +1,7 @@
 package org.folio.okapi.header;
 
-import io.vertx.core.AbstractVerticle;
-import io.vertx.core.Promise;
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
 import io.vertx.core.Vertx;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.json.JsonArray;
@@ -9,7 +9,6 @@
 import io.vertx.core.streams.ReadStream;
 import io.vertx.ext.web.Router;
 import io.vertx.ext.web.RoutingContext;
-import java.io.IOException;
 import java.lang.management.ManagementFactory;
 import java.util.HashMap;
 import java.util.Map;
@@ -22,7 +21,7 @@
  * facilities, like supporting a _tenantPermissions interface.
  *
  */
-public class MainVerticle extends AbstractVerticle {
+public class MainVerticle extends VerticleBase {
 
   private final Logger logger = OkapiLogger.get();
   private Map<String,JsonArray> savedPermissions = new HashMap<>();
@@ -89,7 +88,7 @@ private void myPermResult(RoutingContext ctx) {
   }
 
   @Override
-  public void start(Promise<Void> promise) throws IOException {
+  public Future<?> start() {
     Router router = Router.router(vertx);
 
     final int port = Integer.parseInt(
@@ -102,8 +101,8 @@ public void start(Promise<Void> promise) throws IOException {
     router.get("/permResult").handler(this::myPermResult);
     router.post("/_/tenantPermissions").handler(this::myPermissionHandle);
 
-    vertx.createHttpServer()
+    return vertx.createHttpServer()
         .requestHandler(router)
-        .listen(port).onComplete(result -> promise.handle(result.mapEmpty()));
+        .listen(port);
   }
 }
diff --git a/okapi-test-module/src/main/java/org/folio/okapi/sample/MainVerticle.java b/okapi-test-module/src/main/java/org/folio/okapi/sample/MainVerticle.java
index 1c6124972..848d805d2 100644
--- a/okapi-test-module/src/main/java/org/folio/okapi/sample/MainVerticle.java
+++ b/okapi-test-module/src/main/java/org/folio/okapi/sample/MainVerticle.java
@@ -1,8 +1,9 @@
 package org.folio.okapi.sample;
 
-import io.vertx.core.AbstractVerticle;
+import static io.vertx.core.http.HttpHeaders.CONTENT_TYPE;
+
 import io.vertx.core.Future;
-import io.vertx.core.Promise;
+import io.vertx.core.VerticleBase;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.http.HttpMethod;
 import io.vertx.core.http.HttpServerOptions;
@@ -14,6 +15,7 @@
 import java.io.FileWriter;
 import java.io.IOException;
 import java.lang.management.ManagementFactory;
+import java.util.Objects;
 import org.apache.logging.log4j.Logger;
 import org.folio.okapi.common.HttpResponse;
 import org.folio.okapi.common.ModuleVersionReporter;
@@ -24,14 +26,13 @@
 /*
  * Test module, to be used in Okapi's own unit tests
  */
-
-@java.lang.SuppressWarnings({"squid:S1192"})
-public class MainVerticle extends AbstractVerticle {
+public class MainVerticle extends VerticleBase {
 
   private final Logger logger = OkapiLogger.get();
-  private String helloGreeting;
+  private String helloGreeting =
+      Objects.requireNonNullElse(System.getenv("helloGreeting"), "Hello");
   private String tenantRequests = "";
-  private JsonArray tenantParameters;
+  private JsonArray tenantParameters = null;
 
   // Report the request headers in response headers, body, and/or log
   private void headers(RoutingContext ctx, StringBuilder xmlMsg) {
@@ -86,7 +87,7 @@ private void myStreamHandle(RoutingContext ctx) {
     ctx.response().setStatusCode(200);
     ctx.response().putHeader("X-Handler-header", "OK");
 
-    final String ctype = ctx.request().headers().get("Content-Type");
+    final String ctype = ctx.request().headers().get(CONTENT_TYPE);
     final String accept = ctx.request().headers().get("Accept");
     // see if POSTed text should be converted to XML.. To simulate a real handler
     // with request/response of different content types
@@ -99,9 +100,9 @@ private void myStreamHandle(RoutingContext ctx) {
       msg.append(hv);
     }
     if (xmlConversion) {
-      ctx.response().putHeader("Content-Type", "text/xml");
+      ctx.response().putHeader(CONTENT_TYPE, "text/xml");
     } else if (ctype != null) {
-      ctx.response().putHeader("Content-Type", ctype);
+      ctx.response().putHeader(CONTENT_TYPE, ctype);
     }
 
     String stopper = ctx.request().getHeader("X-stop-here");
@@ -162,7 +163,7 @@ private void myTenantHandle(RoutingContext ctx) {
     } else {
       ctx.response().setChunked(true);
 
-      final String cont = ctx.request().getHeader("Content-Type");
+      final String cont = ctx.request().getHeader(CONTENT_TYPE);
       logger.debug("Tenant api content type: '{}'", cont);
       String tok = ctx.request().getHeader(XOkapiHeaders.TOKEN);
       if (tok == null) {
@@ -225,11 +226,7 @@ private void myPermissionHandle(RoutingContext ctx) {
   }
 
   @Override
-  public void start(Promise<Void> promise) throws IOException {
-    helloGreeting = System.getenv("helloGreeting");
-    if (helloGreeting == null) {
-      helloGreeting = "Hello";
-    }
+  public Future<?> start() {
     final int port = Integer.parseInt(
         System.getProperty("http.port", System.getProperty("port", "8080")));
     String name = ManagementFactory.getRuntimeMXBean().getName();
@@ -253,7 +250,7 @@ public void start(Promise<Void> promise) throws IOException {
     router.get("/recurse").handler(this::recurseHandle);
 
     HttpServerOptions so = new HttpServerOptions().setHandle100ContinueAutomatically(true);
-    Future<Void> future = vertx.createHttpServer(so)
+    return vertx.createHttpServer(so)
         .requestHandler(router)
         .listen(port)
         .compose(result -> {
@@ -270,6 +267,5 @@ public void start(Promise<Void> promise) throws IOException {
           }
           return Future.succeededFuture();
         });
-    future.onComplete(promise::handle);
   }
 }