fixing issue #1

Makefile

@@ -13,4 +13,14 @@ test/run:
 	./k6 run examples/topic_batch_string_message.js
 	./k6 run examples/topic_single_message.js
 	./k6 run examples/topic_single_string_message.js
+	./k6 run examples/bug_application_properties.js
 
+local/compose/up:
+	docker compose up rabbit -d
+	docker compose up sbemulator -d
+	@export CONNECTION_STRING="Endpoint=sb://sbemulator/;SharedAccessKeyName=all;SharedAccessKey=CLwo3FQ3S39Z4pFOQDefaiUd1dSsli4XOAj3Y9Uh1E=;EnableAmqpLinkRedirect=false"
+
+local/compose/down:
+	docker compose down
+
+test/run/local: install compile local/compose/up test/run local/compose/down

examples/bug_application_properties.js

@@ -0,0 +1,49 @@
+import { sleep, check } from 'k6';
+import { ServiceBus } from 'k6/x/azservicebus';
+import { uuidv4 } from 'https://jslib.k6.io/k6-utils/1.4.0/index.js';
+
+const config = {
+    connectionString: __ENV.CONNECTION_STRING,
+    timeout: 30000,
+    insecureSkipVerify: true, // the docker servicebus emulator uses a self-signed cert
+};
+
+const servicebus = new ServiceBus(config);
+const sender = servicebus.createSender('test-topic');
+const receiver = servicebus.createSubscriptionReceiver('test-topic', 'test-sub1');
+const batch_message_count = 2;
+
+export default function () {
+    const data = [];
+
+    for(let i = 0; i < batch_message_count; i++) {
+        var properties = {
+            'Type': "MessageType"
+        };
+
+        data.push({
+            messageID: uuidv4(),
+            applicationProperties: properties,
+            contentType: 'application/json',
+            subject: 'example',
+            bodyAsString: JSON.stringify({ Title: 'Example'}),
+        });
+    }
+
+    sender.sendBatchMessages(data);
+
+    sleep(1);
+
+    const messages = receiver.getMessages(batch_message_count);
+    console.log(messages);
+    console.log(`messages: ${messages.length}`)
+    check(messages, {
+        'Has the expected size': (m) => m.length === batch_message_count,
+    });
+}
+
+export function teardown() {
+    receiver.close();
+    sender.close();
+    servicebus.close();
+}

sender.go

@@ -133,6 +133,7 @@ func (s *Sender) createContext() (context.Context, context.CancelFunc) {
 func mapMessageToSeriveBus(message *Message) *azservicebus.Message {
 	sbMessage := &azservicebus.Message{}
 	if message.ApplicationProperties != nil {
+		sbMessage.ApplicationProperties = make(map[string]any)
 		for k, v := range message.ApplicationProperties {
 			sbMessage.ApplicationProperties[k] = v
 		}