Consider resetting the session when calling drupalLogout() for functional tests

I have a similar problem trying to fix a unit test on a contrib module, but adding $this->getSession()->reset(); did not work. Do you add it right after drupalLogout() ?

An improvement on the error message would be very nice as well because it does not make much sense.

The unit test causing problem is from the redirect_after_login contrib module.

Calling drupalLogout() in this scenario is the problem because assert() fails (its in one of the test traits) - it thinks the session is still authenticated. This does not happen outside of a test.

I believe if the test method was updated to this, it would resolve the issue:

  protected function drupalLogout() {
    // Make a request to the logout page, and redirect to the user page, the
    // idea being if you were properly logged out you should be seeing a login
    // screen.
    $assert_session = $this->assertSession();
    $destination = Url::fromRoute('user.page')->toString();
    $this->drupalGet(Url::fromRoute('user.logout', [], ['query' => ['destination' => $destination]]));
    $assert_session->fieldExists('name');
    $assert_session->fieldExists('pass');

    // @see BrowserTestBase::drupalUserIsLoggedIn()
    unset($this->loggedInUser->sessionId);
    $this->loggedInUser = FALSE;
    $this->getSession()->reset();
    \Drupal::currentUser()->setAccount(new AnonymousUserSession());
  }

Multiple login/logouts in a single test method that alters or adds to user session data or cookie data is otherwise problematic to test.

Ok good to know, thank you very much for the insights !