Description

This test case focuses on graphical login screen, shown after boot, log out, and when user-switching.

Setup

Create multiple user accounts in "User menu" - "System Settings" - "User Accounts". Each account using different keyboard layout for username and password input. For example US QWERTY and FR AZERTY or Dvorak or your local variant.
You can switch between keyboard layouts using layout icon located in upper panel on the left side. For adding new layout select "Region and Language Settings" from icon's menu.
Try to use (special) characters not available on the other keyboard layout or located on different keys. Remember, usernames should contain only English characters, digits and allowed special characters ("." or "-" or "_"), passwords don't have this restriction.
You can set password after you create new account or at first login, try both methods.

Boot or logout to show login screen.
One by one try to login with each listed account. Remember to select correct keyboard layout before you enter your password.
Try to login with wrong password and correct password typed when using wrong keyboard layout.
Login as root using "Not listed?" option. Try other existing accounts, even listed ones.
Try Suspend (if available), Power Off and Restart from login screen.
Use "User menu" - "Switch User" to login with multiple user accounts and switch between them without logging out.

The login manager should display all user accounts, but not the root account. Username should contain correct characters.
You should be able to log in with each configured user account using correct password. Check if keyboard layout is the same as you have selected in login screen, after you login to desktop.
Entering an incorrect password should return you to the accounts list and show error message.
You should be able to login using "Not listed?" option with correct username and password.
Power management options should work as expected. If you can't resume from suspend, it's usually not a bug at login screen, but in hardware drivers which means this test case didn't failed. Feel free to report driver bugs against appropriate components.
You should be able to login with multiple accounts at the same time and switch between them.