Update tests/ActiveFixtureTest.php

Co-authored-by: Alexander Makarov <sam@rmcreative.ru>

Author: ziaratban

tests/ActiveFixtureTest.php

@@ -142,7 +142,7 @@ class {$className} extends \yii\mongodb\ActiveFixture
             'collectionName' => Customer::collectionName(),
         ]);
         $fixture->load();
-        $rows = $this->findAll(yii::$app->mongodb->getCollection(Customer::collectionName()));
+        $rows = $this->findAll(Yii::$app->mongodb->getCollection(Customer::collectionName()));
         $this->assertCount(2, $rows);
 
         $fixture = new $className([