Specify package requirements for module (#3366)

* fixed time calculation. Fixes #3331

* Added RequiresPackage interface and validation to check external package dependencies for modules

Author: DavertMik

src/Codeception/Module/Redis.php

@@ -2,6 +2,7 @@
 
 namespace Codeception\Module;
 
+use Codeception\Lib\Interfaces\RequiresPackage;
 use Codeception\Module as CodeceptionModule;
 use Codeception\TestCase;
 use Codeception\Exception\ModuleException;
@@ -31,7 +32,7 @@
  *
  * @author Marc Verney <[email protected]>
  */
-class Redis extends CodeceptionModule
+class Redis extends CodeceptionModule implements RequiresPackage
 {
     /**
      * {@inheritdoc}
@@ -59,16 +60,18 @@ class Redis extends CodeceptionModule
      */
     public $driver;
 
+    public function _requires()
+    {
+        return ['Predis\Client' => '"predis/predis": "^1.0"'];
+    }
+
     /**
      * Instructions to run after configuration is loaded
      *
      * @throws ModuleException
      */
     public function _initialize()
     {
-        if (!class_exists('Predis\Client')) {
-            throw new ModuleException($this, 'This module requires Predis library to be installed. Please add "predis/predis": "^1.0" to composer.json');
-        }
         try {
             $this->driver = new RedisDriver([
                 'host'     => $this->config['host'],