Reauthenticate behat feature failing on 1.3 branch

[dnsl48]

Affected versions

silverstripe-admin 1.3, 1.3.0

Feature

@modal @retry        
Feature: Reauthenticate
  As a content editor
  I want to be able to log in through a CMS popup when my session expires
  So that I can avoid losing unsaved work

Problem

The same exact commit may pass and break on CI in two consequent builds (e.g. 6ba4a1f on https://travis-ci.org/open-sausages/silverstripe-admin).

Why this happens

1. The Search component that has been introduced in 1.3. Underneath it uses FormBuildLoader, which performs asynchronous call to the server on component mounting.

2. The scenario background after loading the page performs a session expiration.

3. Apparently, sometimes the session expiration step goes ahead of the search component rendering, so that the ajax request to the server triggers a new session generation. At this stage, LeftAndMain controller handles it as a security failure and the Security module registers a session flush message, given by the LeftAndMain controller.

4. Sometimes, at this point the test kicks in before the browser handles the redirect and tries to perform Add Member action.

5. At this point the IFrame with the login form gets rendered with the session flush message, registered in the step 3. Which has different copy from the default one. At this point the scenario fails with the following screenshot:

PRs

• ADD / TestSessionState initial implementation silverstripe-testsession#58
• ADD / After each step we wait for the server to handle all requests silverstripe-behat-extension#185
• MINOR Increment testsession requirement for 4.1 release silverstripe-behat-extension#186
• Cleanup composer reqs, use dev branch of behat extension recipe-testing#3
• Fix behat reauthenticate tests #789
• Fix reauthenticate behat tests #804