yii composer install

tests/codeception/config/functional.php

@@ -0,0 +1,25 @@
+<?php
+$_SERVER['SCRIPT_FILENAME'] = YII_TEST_ENTRY_FILE;
+$_SERVER['SCRIPT_NAME'] = YII_TEST_ENTRY_URL;
+
+/**
+ * Application configuration for functional tests
+ */
+return yii\helpers\ArrayHelper::merge(
+    require(__DIR__ . '/../../../config/web.php'),
+    require(__DIR__ . '/config.php'),
+    [
+        'components' => [
+            'request' => [
+                // it's not recommended to run functional tests with CSRF validation enabled
+                'enableCsrfValidation' => false,
+                // but if you absolutely need it set cookie domain to localhost
+                /*
+                'csrfCookie' => [
+                    'domain' => 'localhost',
+                ],
+                */
+            ],
+        ],
+    ]
+);