How do I call `grabFixture()` method from within `ApiTester instance in Yii2? - yii2

Question

I am building an API in Yii2 2.0.14 and running tests with Codeception. Examples in the tutorial* show that I can call fixtures like so:
$profile = $I->grabFixture('profiles', 'user1');
However this doesn't seem to be available in my test class here:
<?php
namespace frontend\tests\api;
use frontend\tests\ApiTester;
class DemoCest
{
public function _fixtures()
{
return [
'users' => [
'class' => UserFixture::className(),
// fixture data located in tests/_data/user.php
'dataFile' => codecept_data_dir() . 'user.php'
],
];
}
public function demo(ApiTester $I)
{
$users = $I->grabFixture('users');
$I->wantTo('perform actions and see result');
$I->haveHttpHeader('Content-Type', 'application/x-www-form-urlencoded');
$I->sendPOST('/user/test', ['name' => 'davert', 'email' => 'davert#codeception.com']);
$I->seeResponseCodeIs(\Codeception\Util\HttpCode::OK); // 200
$I->seeResponseIsJson();
$I->seeResponseContainsJson(['message' => 'test OK']);
}
}
I have seen that you need to add fixtures to frontend/tests/api-suite.yml but Codeception is throwing an exception when I do that
PHP Notice: Undefined index: tests in
/var/www/vendor/codeception/base/src/Codeception/Command/Run.php on
line 389
I am completely lost.
actor: ApiTester
modules:
enabled:
- Yii2:
part: [orm, email, fixtures]
- \frontend\tests\Helper\Api
- REST:
url: http://securedata.test/api/v1
depends: PhpBrowser
part: Json
Can anyone lead me in the right direction?
tutorial - http://www.yiiframework.com/doc-2.0/guide-test-fixtures.html

Answer 1

Add to your suite configuration, you haven't defined the tests path in the codeception.yml under paths.
If you look into the line the error points to it will take you to the line inside the matchSingleTest function
in your case
list(, $suite, $test) = $this->matchTestFromFilename($suite, $config['paths']['tests']);
in which it gives tests as undefined index for the $config['paths'] array, which if you backtrack parses the codeception.yml to the $config,
You are using an older version of Yii 2.0.14 which may have the missing section from the execute() see this ISSUE
So add tests directory as . and make sure your codeception.yml is in the /tests root.
see the following
paths:
tests: .