tests: add unit tests for maxBytes handling

src/message-queues.ts

@@ -64,7 +64,7 @@ export interface BatchOptions {
 // This is the maximum number of bytes we will send for a batch of
 // ack/modack messages. The server itself has a maximum of 512KiB, so
 // we just pull back a little from that in case of unknown fenceposts.
-const MAX_BATCH_BYTES = 510 * 1024 * 1024;
+export const MAX_BATCH_BYTES = 510 * 1024 * 1024;
 
 /**
  * Error class used to signal a batch failure.

test/message-queues.ts

@@ -24,7 +24,7 @@ import defer = require('p-defer');
 
 import * as messageTypes from '../src/message-queues';
 import {BatchError} from '../src/message-queues';
-import {AckError, Message, Subscriber} from '../src/subscriber';
+import {Message, Subscriber} from '../src/subscriber';
 import {DebugMessage} from '../src/debug';
 
 class FakeClient {
@@ -160,6 +160,15 @@ describe('MessageQueues', () => {
         assert.strictEqual(stub.callCount, 1);
       });
 
+      it('should flush the queue if at byte capacity', () => {
+        const stub = sandbox.stub(messageQueue, 'flush');
+
+        messageQueue.bytes = messageTypes.MAX_BATCH_BYTES - 10;
+        messageQueue.add(new FakeMessage() as Message);
+
+        assert.strictEqual(stub.callCount, 1);
+      });
+
       it('should schedule a flush if needed', () => {
         const clock = sandbox.useFakeTimers();
         const stub = sandbox.stub(messageQueue, 'flush');
@@ -214,6 +223,13 @@ describe('MessageQueues', () => {
         assert.strictEqual(messageQueue.numPendingRequests, 0);
       });
 
+      it('should remove the bytes of messages from the queue', () => {
+        messageQueue.add(new FakeMessage() as Message);
+        messageQueue.flush();
+
+        assert.strictEqual(messageQueue.bytes, 0);
+      });
+
       it('should send the batch', () => {
         const message = new FakeMessage();
         const deadline = 10;