diff --git a/test/realtime/message.test.js b/test/realtime/message.test.js
index 9f54cce7d..d74ba00be 100644
--- a/test/realtime/message.test.js
+++ b/test/realtime/message.test.js
@@ -1438,36 +1438,40 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, Helper, async
 
               // Subscription to check all messages were received as expected
               rtUnfilteredChannel.subscribe('end', function (msg) {
-                try {
-                  expect(msg.data).to.equal(testData[testData.length - 1].data, 'Unexpected msg data received');
-
-                  // Check that we receive expected messages on filtered channel
-                  expect(filteredMessages.length).to.equal(2, 'Expect only two filtered message to be received');
-                  expect(filteredMessages[0].data).to.equal(testData[0].data, 'Unexpected data received');
-                  expect(filteredMessages[1].data).to.equal(testData[2].data, 'Unexpected data received');
-                  expect(filteredMessages[0].extras.headers.name).to.equal(
-                    testData[0].extras.headers.name,
-                    'Unexpected header value received',
-                  );
-                  expect(filteredMessages[1].extras.headers.name).to.equal(
-                    testData[2].extras.headers.name,
-                    'Unexpected header value received',
-                  );
-                  // Check that message with header that doesn't meet filtering condition is not received.
-                  for (msg of filteredMessages) {
-                    expect(msg.extras.headers.number).to.equal(26095, 'Unexpected header filtering value received');
-                  }
+                // ensure we let any pending IO complete as messages may be queued up but not yet
+                // added to filteredMessages
+                setImmediate(() => {
+                  try {
+                    expect(msg.data).to.equal(testData[testData.length - 1].data, 'Unexpected msg data received');
+
+                    // Check that we receive expected messages on filtered channel
+                    expect(filteredMessages.length).to.equal(2, 'Expect only two filtered message to be received');
+                    expect(filteredMessages[0].data).to.equal(testData[0].data, 'Unexpected data received');
+                    expect(filteredMessages[1].data).to.equal(testData[2].data, 'Unexpected data received');
+                    expect(filteredMessages[0].extras.headers.name).to.equal(
+                      testData[0].extras.headers.name,
+                      'Unexpected header value received',
+                    );
+                    expect(filteredMessages[1].extras.headers.name).to.equal(
+                      testData[2].extras.headers.name,
+                      'Unexpected header value received',
+                    );
+                    // Check that message with header that doesn't meet filtering condition is not received.
+                    for (msg of filteredMessages) {
+                      expect(msg.extras.headers.number).to.equal(26095, 'Unexpected header filtering value received');
+                    }
 
-                  // Check that we receive expected messages on unfiltered channel, including the `end` event message
-                  expect(unFilteredMessages.length).to.equal(6, 'Expect only 6 unfiltered message to be received');
-                  for (var i = 0; i < unFilteredMessages.length; i++) {
-                    expect(unFilteredMessages[i].data).to.equal(testData[i].data, 'Unexpected data received');
+                    // Check that we receive expected messages on unfiltered channel, including the `end` event message
+                    expect(unFilteredMessages.length).to.equal(6, 'Expect only 6 unfiltered message to be received');
+                    for (var i = 0; i < unFilteredMessages.length; i++) {
+                      expect(unFilteredMessages[i].data).to.equal(testData[i].data, 'Unexpected data received');
+                    }
+                  } catch (err) {
+                    helper.closeAndFinish(done, realtime, err);
+                    return;
                   }
-                } catch (err) {
-                  helper.closeAndFinish(done, realtime, err);
-                  return;
-                }
-                helper.closeAndFinish(done, realtime);
+                  helper.closeAndFinish(done, realtime);
+                });
               });
               var restChannel = rest.channels.get('chan');
               restChannel.publish(testData);