Added ConditionalOnMissingBeans for Spring Boot app

accurest-messaging/accurest-messaging-core/src/main/java/io/codearte/accurest/messaging/noop/NoOpAccurestMessageBuilder.java

@@ -1,21 +1,21 @@
 package io.codearte.accurest.messaging.noop;
 
+import java.util.Map;
+
 import io.codearte.accurest.messaging.AccurestMessage;
 import io.codearte.accurest.messaging.AccurestMessageBuilder;
 
-import java.util.Map;
-
 /**
  * @author Marcin Grzejszczak
  */
 public class NoOpAccurestMessageBuilder implements AccurestMessageBuilder {
 	@Override
 	public AccurestMessage create(Object o, Map headers) {
-		return null;
+		return new NoOpAccurestMessage();
 	}
 
 	@Override
 	public AccurestMessage create(Object o) {
-		return null;
+		return new NoOpAccurestMessage();
 	}
 }

stub-runner/stub-runner-boot/src/main/groovy/io/codearte/accurest/stubrunner/boot/StubRunnerConfig.groovy

@@ -0,0 +1,28 @@
+package io.codearte.accurest.stubrunner.boot
+
+import io.codearte.accurest.messaging.AccurestMessageBuilder
+import io.codearte.accurest.messaging.AccurestMessaging
+import io.codearte.accurest.messaging.noop.NoOpAccurestMessageBuilder
+import io.codearte.accurest.messaging.noop.NoOpAccurestMessaging
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+
+/**
+ * @author Marcin Grzejszczak
+ */
+@Configuration
+class StubRunnerConfig {
+
+	@Bean
+	@ConditionalOnMissingBean
+	AccurestMessaging noOpAccurestMessaging() {
+		return new NoOpAccurestMessaging()
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	AccurestMessageBuilder noOpAccurestMessageBuilder() {
+		return new NoOpAccurestMessageBuilder()
+	}
+}