Yii2 + Codeception Cookie & Session problem / error, still got no solution for this. The cookie / session won't be share between tests (function). [Edit] check acceptance.yml

acceptance.yml

# Codeception Test Suite Configuration
class_name: AcceptanceTester
modules:
    enabled:
       - WebDriver
    config:
        WebDriver:
            url: http://localhost:8080/
            browser: chrome
            window_size: 1366x768
            clear_cookies: false

codeception.log

$ ../../../vendor/bin/codecept run acceptance --debug
Codeception PHP Testing Framework v2.1.0-rc1
Powered by PHPUnit 4.7.7 by Sebastian Bergmann and contributors.

Tests\codeception\backend.acceptance Tests (3) -------------------------------------------------------------------------------------------
Modules: WebDriver
------------------------------------------------------------------------------------------------------------------------------------------
Test login with valid user (CustomerCest::login)
Scenario:
* I load session snapshot "login"
* As a Fajri
* I am on page "/auth/login/"

  [GET] http://localhost:8080/auth/login/
* I fill field "input[name="LoginForm[username]"]","fajri@ebizu.com"
* I fill field "input[name="LoginForm[password]"]","mnbvcxz"
* I click "Log In"
* I grab cookie "PHPSESSID"
* I save session snapshot "login"
 PASSED

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
See if all the Menu is ok (CustomerCest::testMenu)
Scenario:
* I set cookie "PHPSESSID","9v1eqhgujod77dl7fk1hbtnk25"

  [Cookies] [{"path":"/","domain":"localhost:8080","name":"PHPSESSID","httpOnly":false,"hCode":-1505796059,"secure":false,"value":"9v1eqhgujod77dl7fk1hbtnk25","class":"org.openqa.selenium.Cookie"}]
* As a Loggedin User
* I pause execution
The execution has been paused. Press ENTER to continue

* I see current url equals "/dashboard/index"
* I pause execution
The execution has been paused. Press ENTER to continue

* I am on page "/customer/index"
  [GET] http://localhost:8080/customer/index
* I see "Customer"
* I pause execution
The execution has been paused. Press ENTER to continue

 PASSED

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Test create (CustomerCest::testCreate)
Scenario:
* I set cookie "PHPSESSID","9v1eqhgujod77dl7fk1hbtnk25"

  [Cookies] [{"path":"/","domain":"localhost:8080","name":"PHPSESSID","httpOnly":false,"hCode":-1505796059,"secure":false,"value":"9v1eqhgujod77dl7fk1hbtnk25","class":"org.openqa.selenium.Cookie"}]
  9v1eqhgujod77dl7fk1hbtnk25
* I pause execution
The execution has been paused. Press ENTER to continue

* I am on page "/customer/index"
  [GET] http://localhost:8080/customer/index
* I see "Customer"
  Screenshot and page source were saved into '_output' dir
 FAIL

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
------------------------------------------------------------------------------------------------------------------------------------------


Time: 28.28 seconds, Memory: 11.00Mb

There was 1 failure:

---------
1) Failed to test create in CustomerCest::testCreate (.\acceptance\CustomerCest.php)

Failed asserting that   /auth/login
--> Log in to get started
Username
Password
Remember Me
›
--> contains "customer".

CustomerCest.php

<?php

// use tests\codeception\backend\AcceptanceTester;
use tests\codeception\backend\acceptance\BaseStep;

class CustomerCest
{
    public $user = 'Fajri';

    // private $cookie = 'xyz';
    private $cookie = null;

    public static $username = 'fajri@ebizu.com';
    public static $password = 'mnbvcxz';

    public function login(BaseStep $I)
    {
        if ($I->loadSessionSnapshot('login')) return;

        $I->am($this->user);
        $I->wantTo('test login with valid user');
        $I->amOnPage('/auth/login/');
        $I->fillField('input[name="LoginForm[username]"]', self::$username);
        $I->fillField('input[name="LoginForm[password]"]', self::$password);
        $I->click('Log In');
        $this->cookie = $I->grabCookie('PHPSESSID');
        // $I->pauseExecution();
        // echo $this->cookie;
        // codecept_debug($this->cookie);

        // saving snapshot
         $I->saveSessionSnapshot('login');
         // $I->pauseExecution();
    }

    /**
     * @depends login
     */
    public function testMenu(BaseStep $I)
    {
        // if ($I->loadSessionSnapshot('login')) return;
        // $I->pauseExecution();
        $I->setCookie('PHPSESSID', $this->cookie);
        $I->am('Loggedin User');
        $I->wantTo('see if all the Menu is ok');

        // Dashboard
        // $I->amOnPage('/');
        $I->pauseExecution();
        $I->seeCurrentUrlEquals('/dashboard/index');
        // $I->see('xyz');

        // // Customer
        // $I->click('Customers');
        $I->pauseExecution();
        $I->amOnPage('/customer/index');
        // $I->amOnPage('/customer/index');
        // $I->pauseExecution();
        $I->see('Customer');
        $I->pauseExecution();
    }

    /**
     * @depends login
     */
    public function testCreate(BaseStep $I)
    {
        // $I->loadSessionSnapshot('login');
        // $I->seeCurrentUrlEquals('/dashboard/index');
        $I->setCookie('PHPSESSID', $this->cookie);
        codecept_debug($this->cookie);
        $I->pauseExecution();

        $I->amOnPage('/customer/index');
        $I->see('Customer');
        $I->pauseExecution();
        // $I->click('New Customer');
        // $I->pauseExecution();
    }
}

Selenium.log

$ java -Dwebdriver.chrome.driver=./chromedriver.exe -jar selenium-server-standal one-2.43.1.jar
22:37:49.451 INFO - Launching a standalone server
22:37:49.572 INFO - Java: Oracle Corporation 25.40-b25
22:37:49.572 INFO - OS: Windows 8.1 6.3 amd64
22:37:49.600 INFO - v2.43.1, with Core v2.43.1. Built from revision 5163bce
22:37:49.800 INFO - RemoteWebDriver instances should connect to: http://127.0.0.1:4444/wd/hub
22:37:49.802 INFO - Version Jetty/5.1.x
22:37:49.804 INFO - Started HttpContext[/selenium-server,/selenium-server]
22:37:49.890 INFO - Started org.openqa.jetty.jetty.servlet.ServletHandler@2aaf7cc2
22:37:49.891 INFO - Started HttpContext[/wd,/wd]
22:37:49.891 INFO - Started HttpContext[/selenium-server/driver,/selenium-server/driver]
22:37:49.891 INFO - Started HttpContext[/,/]
22:37:49.900 INFO - Started SocketListener on 0.0.0.0:4444
22:37:49.901 INFO - Started org.openqa.jetty.jetty.Server@133314b
22:38:00.389 INFO - Executing: [new session: Capabilities [{browserName=chrome}]])
22:38:00.414 INFO - Creating a new session for Capabilities [{browserName=chrome}]
Starting ChromeDriver (v2.9.248315) on port 34781
22:38:02.539 INFO - Done: [new session: Capabilities [{browserName=chrome}]]
22:38:03.080 INFO - Executing: [implicitly wait: 0])
22:38:03.090 INFO - Done: [implicitly wait: 0]
22:38:03.598 INFO - Executing: [set window size])
22:38:06.732 INFO - Done: [set window size]
22:38:06.909 INFO - Executing: [get: http://localhost:8080/auth/login/])
22:38:10.322 INFO - Done: [get: http://localhost:8080/auth/login/]
22:38:10.449 INFO - Executing: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')][(((./@name = 'input[name="LoginForm[username]"]') or ./@id = //label[contains(normalize-space(string(.)), 'input[name="LoginForm[username]"]')]/@for) or ./@placeholder = 'input[name="LoginForm[username]"]')] | .//label[contains(normalize-space(string(.)), 'input[name="LoginForm[username]"]')]//.//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')]])
22:38:10.488 INFO - Done: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')][(((./@name = 'input[name="LoginForm[username]"]') or ./@id = //label[contains(normalize-space(string(.)), 'input[name="LoginForm[username]"]')]/@for) or ./@placeholder = 'input[name="LoginForm[username]"]')] | .//label[contains(normalize-space(string(.)), 'input[name="LoginForm[username]"]')]//.//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')]]
22:38:10.492 INFO - Executing: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][@name = 'input[name="LoginForm[username]"]']])
22:38:10.521 INFO - Done: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][@name = 'input[name="LoginForm[username]"]']]
22:38:10.535 INFO - Executing: [find elements: By.selector: input[name="LoginForm[username]"]])
22:38:10.582 INFO - Done: [find elements: By.selector: input[name="LoginForm[username]"]]
22:38:10.607 INFO - Executing: [clear: 0 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[username]"]]])
22:38:10.649 INFO - Done: [clear: 0 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[username]"]]]
22:38:10.656 INFO - Executing: [send keys: 0 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[username]"]], [fajri@ebizu.com]])
22:38:10.740 INFO - Done: [send keys: 0 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[username]"]], [fajri@ebizu.com]]
22:38:10.764 INFO - Executing: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')][(((./@name = 'input[name="LoginForm[password]"]') or ./@id = //label[contains(normalize-space(string(.)), 'input[name="LoginForm[password]"]')]/@for) or ./@placeholder = 'input[name="LoginForm[password]"]')] | .//label[contains(normalize-space(string(.)), 'input[name="LoginForm[password]"]')]//.//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')]])
22:38:10.832 INFO - Done: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')][(((./@name = 'input[name="LoginForm[password]"]') or ./@id = //label[contains(normalize-space(string(.)), 'input[name="LoginForm[password]"]')]/@for) or ./@placeholder = 'input[name="LoginForm[password]"]')] | .//label[contains(normalize-space(string(.)), 'input[name="LoginForm[password]"]')]//.//*[self::input | self::textarea | self::select][not(./@type = 'submit' or ./@type = 'image' or ./@type = 'hidden')]]
22:38:10.839 INFO - Executing: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][@name = 'input[name="LoginForm[password]"]']])
22:38:10.873 INFO - Done: [find elements: By.xpath: .//*[self::input | self::textarea | self::select][@name = 'input[name="LoginForm[password]"]']]
22:38:10.881 INFO - Executing: [find elements: By.selector: input[name="LoginForm[password]"]])
22:38:10.917 INFO - Done: [find elements: By.selector: input[name="LoginForm[password]"]]
22:38:10.922 INFO - Executing: [clear: 1 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[password]"]]])
22:38:10.957 INFO - Done: [clear: 1 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[password]"]]]
22:38:10.962 INFO - Executing: [send keys: 1 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[password]"]], [mnbvcxz]])
22:38:11.059 INFO - Done: [send keys: 1 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: input[name="LoginForm[password]"]], [mnbvcxz]]
22:38:11.072 INFO - Executing: [find elements: By.selector: Log In])
22:38:11.110 INFO - Done: [find elements: By.selector: Log In]
22:38:11.161 INFO - Executing: [find elements: By.xpath: .//a[normalize-space(.)='Log In'] | .//button[normalize-space(.)='Log In'] | .//a/img[normalize-space(@alt)='Log In']/ancestor::a | .//input[./@type = 'submit' or ./@type = 'image' or ./@type = 'button'][normalize-space(@value)='Log In']])
22:38:11.198 INFO - Done: [find elements: By.xpath: .//a[normalize-space(.)='Log In'] | .//button[normalize-space(.)='Log In'] | .//a/img[normalize-space(@alt)='Log In']/ancestor::a | .//input[./@type = 'submit' or ./@type = 'image' or ./@type = 'button'][normalize-space(@value)='Log In']]
22:38:11.205 INFO - Executing: [click: 2 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> xpath: .//a[normalize-space(.)='Log In'] | .//button[normalize-space(.)='Log In'] | .//a/img[normalize-space(@alt)='Log In']/ancestor::a | .//input[./@type = 'submit' or ./@type = 'image' or ./@type = 'button'][normalize-space(@value)='Log In']]])
22:38:11.292 INFO - Done: [click: 2 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> xpath: .//a[normalize-space(.)='Log In'] | .//button[normalize-space(.)='Log In'] | .//a/img[normalize-space(@alt)='Log In']/ancestor::a | .//input[./@type = 'submit' or ./@type = 'image' or ./@type = 'button'][normalize-space(@value)='Log In']]]
22:38:11.298 INFO - Executing: [get all cookies])
22:38:11.317 INFO - Done: [get all cookies]
22:38:11.323 INFO - Executing: [get all cookies])
22:38:11.328 INFO - Done: [get all cookies]
22:38:11.336 INFO - Executing: [delete all cookies])
22:38:11.380 INFO - Done: [delete all cookies]
22:38:11.405 INFO - Executing: [add cookie: PHPSESSID=9v1eqhgujod77dl7fk1hbtnk25; path=/])
22:38:11.426 INFO - Done: [add cookie: PHPSESSID=9v1eqhgujod77dl7fk1hbtnk25; path=/]
22:38:11.429 INFO - Executing: [get all cookies])
22:38:11.437 INFO - Done: [get all cookies]
22:38:18.273 INFO - Executing: [get current url])
22:38:18.288 INFO - Done: [get current url]
22:38:20.018 INFO - Executing: [get: http://localhost:8080/customer/index])
22:38:20.628 INFO - Done: [get: http://localhost:8080/customer/index]
22:38:20.633 INFO - Executing: [find elements: By.selector: body])
22:38:20.666 INFO - Done: [find elements: By.selector: body]
22:38:20.670 INFO - Executing: [get text: 3 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: body]])
22:38:20.807 INFO - Done: [get text: 3 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: body]]
22:38:20.813 INFO - Executing: [get current url])
22:38:20.818 INFO - Done: [get current url]
22:38:21.941 INFO - Executing: [delete all cookies])
22:38:21.991 INFO - Done: [delete all cookies]
22:38:22.001 INFO - Executing: [add cookie: PHPSESSID=9v1eqhgujod77dl7fk1hbtnk25; path=/])
22:38:22.009 INFO - Done: [add cookie: PHPSESSID=9v1eqhgujod77dl7fk1hbtnk25; path=/]
22:38:22.019 INFO - Executing: [get all cookies])
22:38:22.022 INFO - Done: [get all cookies]
22:38:23.434 INFO - Executing: [get: http://localhost:8080/customer/index])
22:38:23.875 INFO - Done: [get: http://localhost:8080/customer/index]
22:38:23.880 INFO - Executing: [find elements: By.selector: body])
22:38:23.934 INFO - Done: [find elements: By.selector: body]
22:38:23.937 INFO - Executing: [get text: 4 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: body]])
22:38:24.054 INFO - Done: [get text: 4 [[ChromeDriver: chrome on WIN8_1 (f9aaaf56c10a125eed177093fd5218cd)] -> css selector: body]]
22:38:24.056 INFO - Executing: [get current url])
22:38:24.062 INFO - Done: [get current url]
22:38:24.086 INFO - Executing: [take screenshot])
22:38:24.338 INFO - Done: [take screenshot]
22:38:24.355 INFO - Executing: [get page source])
22:38:24.381 INFO - Done: [get page source]
22:38:24.395 INFO - Executing: [delete all cookies])
22:38:24.452 INFO - Done: [delete all cookies]
22:38:24.456 INFO - Executing: [delete session: 5c2b9c45-58c8-4db9-99e1-f82393160f6c])
22:38:25.697 INFO - Done: [delete session: 5c2b9c45-58c8-4db9-99e1-f82393160f6c]

Please see:
https://github.com/Codeception/Codeception/issues/4476
for a workaround, which is from @yujin1st :

For all who's tired with waiting, i suggest temporary solution to add a line into vendor/phpunit/phpunit/src/Util/Printer.php:43:

    if (!$out) $out = 'php://stderr';