Connection unit testing in Python

Question

I am new to Python unit testing and I am not sure how i can create a unit test of this function that returns a connection?

def connection(self):
    connection = mysql.connector.connect(host='localhost', 
                     database='test',
                     user='user', 
                     password='password',
                     auth_plugin='mysql_native_password')
    return connection

Answer 1

You could mock out mysql.connector.connect and ensure that it's called, but honestly this is probably too small a unit to provide any benefits to your unit tests. This is just delegating a call to mysql.connector.connect, which itself should be tested (by the mysql package).

class TestConnection(unittest.TestCase):
    @unittest.mock('module_under_test.mysql.connector.connect')
    def test_connection(self, mockconnect):
        module_under_test.connection()
        mockconnect.assert_called()

I suppose you could also check to make sure that it always returns something (to keep from future revisions forgetting to return out of the function.

    # inside test_connection as above
        connection = module_under_test.connection()
        self.assertIsNotNone(connection)
        mockconnect.assert_called()