I'll be more specific,
- there is a special .env.test file 
test/_bootstrap.php
define('ENV', '.env.test');
codeception.yml
modules:
    config:
        Db:
            dsn: 'mysql:host=localhost;dbname=test'
            user: 'test'
            password: 'test'
            dump: tests/_data/dump.sql
api.suite.yml
class_name: ApiTester
modules:
    enabled:
        - \Helper\Api
        - \Helper\JsonSchema
        - Db:
            cleanup: true
        - REST:
            depends: PhpBrowser
            url: https://localhost:8888
            part: Json
defined('ENV') or define('ENV', '.env');
$dotenv = new \Dotenv\Dotenv(__DIR__.'/../', ENV);
$dotenv->load();
So, when request is created via PhpBrowser module, it doesn't use a '.env.test' but '.env' like a regular request to API, should I use Phalcon2 module for REST, or there is some better way to load a test database?