Sometimes we need our tests to check if an exception was generated. A common case is when testing if some validations are being done properly.

In our example, the test_count() method uses a Warning exception as a way to give information to the user. To check if an exception is raised, we place the corresponding code inside a with self.assertRaises() block.

We need to import the Warning exception at the top of the file:

from odoo.exceptions import Warning

And add to the test class a method with another test case:

def test_count(self): 
    "Test count button" 
    with self.assertRaises(Warning) as e: 
        self.wizard.do_count_tasks() 
    self.assertIn(' 2 ', str(e.exception)) 

If the do_count_tasks() method does not raise an exception, the check will fail. If it does raise that exception, the check succeeds and the exception raised is stored in the e variable.

We use that to further inspect it. The exception message contains the number of...