From 4ec852d28817e01f3119b2eb04618adc6d79e90e Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Wed, 13 Nov 2019 17:49:07 -0500
Subject: [PATCH 1/2] fix(connection): bubble up connected/disconnected events
 with unified topology

---
 lib/connection.js       | 6 ++++++
 test/connection.test.js | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/connection.js b/lib/connection.js
index 785796c1f50..6cdd4e64dc5 100644
--- a/lib/connection.js
+++ b/lib/connection.js
@@ -643,6 +643,12 @@ Connection.prototype.openUri = function(uri, options, callback) {
       if (options.useUnifiedTopology) {
         if (type === 'Single') {
           const server = Array.from(db.s.topology.s.servers.values())[0];
+          server.s.pool.on('close', () => {
+            _this.readyState = STATES.disconnected;
+          });
+          server.s.topology.on('serverHeartbeatSucceeded', () => {
+            _handleReconnect();
+          });
           server.s.pool.on('reconnect', () => {
             _handleReconnect();
           });
diff --git a/test/connection.test.js b/test/connection.test.js
index 6a4a61a4697..f7c4a4e4852 100644
--- a/test/connection.test.js
+++ b/test/connection.test.js
@@ -189,7 +189,7 @@ describe('connections:', function() {
         let numReconnected = 0;
         let numReconnect = 0;
         let numClose = 0;
-        const conn = mongoose.createConnection('mongodb://localhost:27000/mongoosetest', {
+        const conn = mongoose.createConnection('mongodb://localhost:27000/mongoosetest?heartbeatfrequencyms=1000', {
           useNewUrlParser: true,
           useUnifiedTopology: true
         });

From e5c6ded7996953b4fe146e6ce9a75041a7849509 Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Thu, 14 Nov 2019 10:22:55 -0500
Subject: [PATCH 2/2] test(connection): fix tests re: #8337

---
 lib/connection.js       | 3 ---
 test/connection.test.js | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/connection.js b/lib/connection.js
index 6cdd4e64dc5..a8e418f49a9 100644
--- a/lib/connection.js
+++ b/lib/connection.js
@@ -652,9 +652,6 @@ Connection.prototype.openUri = function(uri, options, callback) {
           server.s.pool.on('reconnect', () => {
             _handleReconnect();
           });
-          server.s.pool.on('reconnectFailed', () => {
-            _this.emit('reconnectFailed');
-          });
           server.s.pool.on('timeout', () => {
             _this.emit('timeout');
           });
diff --git a/test/connection.test.js b/test/connection.test.js
index f7c4a4e4852..16b05ac3305 100644
--- a/test/connection.test.js
+++ b/test/connection.test.js
@@ -260,7 +260,7 @@ describe('connections:', function() {
           reconnectTries: 3,
           reconnectInterval: 100,
           useNewUrlParser: true,
-          useUnifiedTopology: true
+          useUnifiedTopology: false // reconnectFailed doesn't get emitted with 'useUnifiedTopology'
         });
 
         conn.on('connected', function() {