diff --git a/composer.json b/composer.json
index 6a062273..9afaad51 100644
--- a/composer.json
+++ b/composer.json
@@ -8,14 +8,20 @@
         "evenement/evenement": "^3.0 || ^2.0 || ^1.0",
         "react/dns": "^1.1",
         "react/event-loop": "^1.0 || ^0.5 || ^0.4 || ^0.3.5",
-        "react/promise": "^2.6.0 || ^1.2.1",
-        "react/promise-timer": "^1.4.0",
+        "react/promise": "dev-master as 2.999.999",
+        "react/promise-timer": "dev-promise-3 as 1.6.0",
         "react/stream": "^1.1"
     },
     "require-dev": {
         "clue/block-react": "^1.2",
         "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
     },
+    "repositories": [
+        {
+            "type": "vcs",
+            "url": "https://github.com/WyriHaximus-labs/promise-timer"
+        }
+    ],
     "autoload": {
         "psr-4": {
             "React\\Socket\\": "src"
diff --git a/tests/DnsConnectorTest.php b/tests/DnsConnectorTest.php
index d3399ea8..982e1a29 100644
--- a/tests/DnsConnectorTest.php
+++ b/tests/DnsConnectorTest.php
@@ -23,7 +23,7 @@ public function setUp()
     public function testPassByResolverIfGivenIp()
     {
         $this->resolver->expects($this->never())->method('resolve');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('127.0.0.1:80'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('127.0.0.1:80'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('127.0.0.1:80');
     }
@@ -31,7 +31,7 @@ public function testPassByResolverIfGivenIp()
     public function testPassThroughResolverIfGivenHost()
     {
         $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(Promise\resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('google.com:80');
     }
@@ -39,7 +39,7 @@ public function testPassThroughResolverIfGivenHost()
     public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     {
         $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(Promise\resolve('::1')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('google.com:80');
     }
@@ -47,7 +47,7 @@ public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     public function testPassByResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->never())->method('resolve');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://127.0.0.1:80/path?query#fragment');
     }
@@ -55,7 +55,7 @@ public function testPassByResolverIfGivenCompleteUri()
     public function testPassThroughResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(Promise\resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/path?query#fragment');
     }
@@ -63,7 +63,7 @@ public function testPassThroughResolverIfGivenCompleteUri()
     public function testPassThroughResolverIfGivenExplicitHost()
     {
         $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(Promise\resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.de');
     }
diff --git a/tests/HappyEyeBallsConnectorTest.php b/tests/HappyEyeBallsConnectorTest.php
index cb7a0aa2..317c0daf 100644
--- a/tests/HappyEyeBallsConnectorTest.php
+++ b/tests/HappyEyeBallsConnectorTest.php
@@ -81,7 +81,7 @@ public function testPassByResolverIfGivenIp()
     public function testPassByResolverIfGivenIpv6()
     {
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('[::1]:80');
 
@@ -91,7 +91,7 @@ public function testPassByResolverIfGivenIpv6()
     public function testPassThroughResolverIfGivenHost()
     {
         $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(Promise\resolve(array('1.2.3.4'))));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('google.com:80');
 
@@ -101,7 +101,7 @@ public function testPassThroughResolverIfGivenHost()
     public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     {
         $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(Promise\resolve(array('::1'))));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('google.com:80');
 
@@ -111,7 +111,7 @@ public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     public function testPassByResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://127.0.0.1:80/path?query#fragment');
 
@@ -121,7 +121,7 @@ public function testPassByResolverIfGivenCompleteUri()
     public function testPassThroughResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(Promise\resolve(array('1.2.3.4'))));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/path?query#fragment');
 
@@ -131,7 +131,7 @@ public function testPassThroughResolverIfGivenCompleteUri()
     public function testPassThroughResolverIfGivenExplicitHost()
     {
         $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(Promise\resolve(array('1.2.3.4'))));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.de');
 
@@ -171,12 +171,12 @@ public function testIpv6ResolvesFirstSoIsTheFirstToConnect(array $ipv6, array $i
 
         $this->resolver->expects($this->at(0))->method('resolveAll')->with('google.com', Message::TYPE_AAAA)->will($this->returnValue(Promise\resolve($ipv6)));
         $this->resolver->expects($this->at(1))->method('resolveAll')->with('google.com', Message::TYPE_A)->will($this->returnValue($deferred->promise()));
-        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(']:80/?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(']:80/?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.com');
 
         $this->loop->addTimer(0.07, function () use ($deferred) {
-            $deferred->reject();
+            $deferred->reject(new \Exception('reject'));
         });
 
         $this->loop->run();
@@ -191,12 +191,12 @@ public function testIpv6DoesntResolvesWhileIpv4DoesFirstSoIpv4Connects(array $ip
 
         $this->resolver->expects($this->at(0))->method('resolveAll')->with('google.com', Message::TYPE_AAAA)->will($this->returnValue($deferred->promise()));
         $this->resolver->expects($this->at(1))->method('resolveAll')->with('google.com', Message::TYPE_A)->will($this->returnValue(Promise\resolve($ipv4)));
-        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(':80/?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(':80/?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.com');
 
         $this->loop->addTimer(0.07, function () use ($deferred) {
-            $deferred->reject();
+            $deferred->reject(new \Exception('reject'));
         });
 
         $this->loop->run();
@@ -290,10 +290,10 @@ public function testAttemptsToConnectBothIpv6AndIpv4AddressesAlternatingIpv6AndI
         $i = 0;
         while (count($ipv6) > 0 || count($ipv4) > 0) {
             if (count($ipv6) > 0) {
-                $this->tcp->expects($this->at($i++))->method('connect')->with($this->equalTo('scheme://[' . array_shift($ipv6) . ']:80/?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+                $this->tcp->expects($this->at($i++))->method('connect')->with($this->equalTo('scheme://[' . array_shift($ipv6) . ']:80/?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
             }
             if (count($ipv4) > 0) {
-                $this->tcp->expects($this->at($i++))->method('connect')->with($this->equalTo('scheme://' . array_shift($ipv4) . ':80/?hostname=google.com'))->will($this->returnValue(Promise\reject()));
+                $this->tcp->expects($this->at($i++))->method('connect')->with($this->equalTo('scheme://' . array_shift($ipv4) . ':80/?hostname=google.com'))->will($this->returnValue(Promise\reject(new \Exception('reject'))));
             }
         }