'Scenario: if the instructor uploads a csv file with no username or email column, an error message is presented.
Given I have a course with cohorting enabled
When I go to the cohort management section of the instructor dashboard
And I upload a CSV file that is missing both the username and email columns
Then I get an error message stating that the file must have either a username or email column'

def test_cohort_by_csv_missing_user(self):

    self.cohort_management_page.upload_cohort_file('cohort_users_missing_user_columns.csv')
    self._verify_cohort_by_csv_notification("The    file    must    contain    a    'username'    column,    an    'email'    column,    or    both.")
