The functional test cases are :
The new task to be assigned : Consider the case of assigning a new task to an appropriate user.
Description : Create a new task and assign it to an appropriate user.
Preconditions : When the user gets assigned, he/she should be enabled to receive email notifications.
Steps :
Create two separate user profiles, each with an email address.
Create a new task using one of the accounts.
Assign the task to your other user account.
Expected result : The user should receive an email confirming that they are assigned a task.