Improve test suite by testing against PHP 7.2 and fix risky tests

.travis.yml

@@ -7,6 +7,7 @@ php:
   - 5.6
   - 7.0
   - 7.1
+  - 7.2
   - hhvm # ignore errors, see below
 
 # lock distro so new future defaults will not break the build

tests/ClientTest.php

@@ -15,6 +15,9 @@ public function setUp()
         $this->client = new Client($this->stream, $this->protocol, $this->splitter);
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testCtorOptionalArgs()
     {
         $this->stream = $this->getMockBuilder('React\Stream\DuplexStreamInterface')->getMock();

tests/FactoryTest.php

@@ -16,6 +16,9 @@ public function setUp()
         $this->factory = new Factory($this->loop, $this->connector, $this->prober);
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testCtorOptionalArgs()
     {
         new Factory($this->loop);

tests/FunctionalTest.php

@@ -43,6 +43,9 @@ public function setUp()
         }
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testCreateClient()
     {
         $factory = new Factory(self::$loop);
@@ -164,6 +167,7 @@ public function testWriteHeartBeatDefaultsToCurrentTime(Client $client)
 
     /**
      * @depends testCreateClient
+     * @doesNotPerformAssertions
      */
     public function testClose(Client $client)
     {