AccountSwitcherTest.php

<?php

namespace Drupal\KernelTests\Core\Session;

use Drupal\Core\Session\UserSession;
use Drupal\KernelTests\KernelTestBase;

/**
 * Test case for account switching.
 *
 * @group Session
 */
class AccountSwitcherTest extends KernelTestBase {
    public function testAccountSwitching() {
        $session_handler = $this->container
            ->get('session_handler.write_safe');
        $user = $this->container
            ->get('current_user');
        $switcher = $this->container
            ->get('account_switcher');
        $original_user = $user->getAccount();
        $original_session_saving = $session_handler->isSessionWritable();
        // Switch to user with uid 2.
        $switcher->switchTo(new UserSession([
            'uid' => 2,
        ]));
        // Verify that the active user has changed, and that session saving is
        // disabled.
        $this->assertEqual($user->id(), 2, 'Switched to user 2.');
        $this->assertFalse($session_handler->isSessionWritable(), 'Session saving is disabled.');
        // Perform a second (nested) user account switch.
        $switcher->switchTo(new UserSession([
            'uid' => 3,
        ]));
        $this->assertEqual($user->id(), 3, 'Switched to user 3.');
        // Revert to the user session that was active between the first and second
        // switch.
        $switcher->switchBack();
        // Since we are still in the account from the first switch, session handling
        // still needs to be disabled.
        $this->assertEqual($user->id(), 2, 'Reverted to user 2.');
        $this->assertFalse($session_handler->isSessionWritable(), 'Session saving still disabled.');
        // Revert to the original account which was active before the first switch.
        $switcher->switchBack();
        // Assert that the original account is active again, and that session saving
        // has been re-enabled.
        $this->assertEqual($user->id(), $original_user->id(), 'Original user correctly restored.');
        $this->assertEqual($session_handler->isSessionWritable(), $original_session_saving, 'Original session saving correctly restored.');
        // Verify that AccountSwitcherInterface::switchBack() will throw
        // an exception if there are no accounts left in the stack.
        $this->expectException(\RuntimeException::class);
        $this->expectExceptionMessage('No more accounts to revert to.');
        $switcher->switchBack();
    }

}