codeception数据库模块错误

我正试图在codeception中创建一个功能测试，在这里我可以检查数据库表是否被使用

<?php 
 $I = new FunctionalTester($scenario);
 $I->am('A guest');
 $I->wantTo('Sign up for an account');
 $I->amOnPage('auth/register');
 $I->fillField('username', 'testuser');
 $I->fillField('first_name', 'test_name');
 $I->fillField('last_name', 'test_last');
 $I->fillField('email', 'test@test.com');
 $I->fillField('password', 'test');
 $I->click('Sign up!');
 $I->seeInDatabase('users', ['username' => 'testuser', 'first_name' => 'test_name', 'last_name' => 'test_last', 'email' => 'test@test.com', 'slug' => 'testuser']);

这是yaml文件：

class_name: FunctionalTester
modules:
    enabled: [Filesystem, FunctionalHelper, Db, PhpBrowser]
    config:
      Db:
         dsn: 'mysql:host=localhost;dbname='db''
         user: 'root'
         password: 'pass!'
         dump: 'tests/_data/dump.sql'
         populate: true
         cleanup: false
      PhpBrowser:
        url: 'http://localhost:8000'

我得到错误：

   Couldn't see in database "users",    {"username":"testuser","first_name":"test_name","last_name":"test_last","email":"test@test.com","slug":"testuser"}:
No matching records found
Failed asserting that '0' is greater than 0.

但是，当我在浏览器中填写表单时，代码会工作，并且用户已注册