Magento 2: "Unable to locate element: .page-header .admin-user" when running FTF

Question

I try to run Functional Testing Framework. When I run tests:

vendor/bin/phpunit

I see that new Firefox window is launched, .../admin/admin/ page is opened and login form is appeared on the page. But authentication is not performed. I see this error in the selenium server logs:

14:21:06.806 INFO - Executing: [get current url])
14:21:06.812 INFO - Done: [get current url]
14:21:06.835 INFO - Executing: [execute script: return document['readyState'], []])
14:21:06.850 INFO - Done: [execute script: return document['readyState'], []]
14:21:06.854 INFO - Executing: [execute script: return document['readyState'], []])
14:21:06.864 INFO - Done: [execute script: return document['readyState'], []]
14:21:06.870 INFO - Executing: [find element: By.cssSelector: .page-header .admin-user])
14:21:07.478 WARN - Exception thrown
org.openqa.selenium.NoSuchElementException: Unable to locate element: .page-header .admin-user

There is no '.page-header' element on the login page:

What I need to do to run functional tests using FTF?

Answer 1

I found out the problem. It deals with new version selenium server 3.0.1 and new Firefox version 50. The problem is following:

I have Firefox v50 and selenium server 3.0.1
This version of the selenium server ask web-driver, I run it using java -Dwebdriver.gecko.driver="path\to\driver\geckodriver.exe" -jar D:\etc\selenium\selenium-server-standalone-3.0.1.jar
But received errors:
Unable to locate element: .page-header .admin-user - in the server trace
moveto did not match a known command - in the test trace
Googled this problem I found that Actions Class not working with gecko driver - so I test couldn't login and returned the error about ".page-header .admin-user"
After I changed Firefox version to 46 and selenium-server to 2.53 everything works well