Manual app reset (#4928)

* Due to modules keeping references to the client, destructor is not a good place for clean up. Instead manually reset application in _after

* Fix pdoCache never being filled

* Improved garbage collection, fixes #4926

Author: SamMousa

src/Codeception/Lib/Connector/Yii2.php

@@ -96,6 +96,8 @@ public function resetApplication()
             \yii\base\Event::offAll();
         }
         Yii::setLogger(null);
+        // This resolves an issue with database connections not closing properly.
+        gc_collect_cycles();
     }
 
     public function startApp()
@@ -284,16 +286,6 @@ protected function mockMailer(array $config)
         return $config;
     }
 
-    /**
-     * A new client is created for every test, it is destroyed after every test.
-     * @see InnerBrowser::_after()
-     *
-     */
-    public function __destruct()
-    {
-        $this->resetApplication();
-    }
-
     public function restart()
     {
         parent::restart();

src/Codeception/Module/Yii2.php

@@ -358,6 +358,8 @@ public function _after(TestInterface $test)
         if ($this->client !== null && $this->client->getApplication()->has('session', true)) {
             $this->client->getApplication()->session->close();
         }
+
+        $this->client->resetApplication();
         parent::_after($test);
     }
 
@@ -385,6 +387,8 @@ public function connectionOpenHandler(Event $event)
              */
             if (isset($this->pdoCache[$key])) {
                 $connection->pdo = $this->pdoCache[$key];
+            } else {
+                $this->pdoCache[$key] = $connection->pdo;
             }
 
             if (isset($this->dsnCache[$connection->dsn])