Test for non-ascii usernames
----------------------------

Let's import a subset of the sample data with a cell containing some
usernames with non-ascii characters:

    >>> browser = Browser('manager', 'schooltool')
    >>> browser.getLink('Manage').click()
    >>> browser.getLink('XLS Import').click()
    >>> import pkg_resources
    >>> browser.getControl('XLS File').add_file(
    ...     pkg_resources.resource_stream('schooltool.export.ftests', 'test_non_ascii_data.xls'),
    ...     'application/excel',
    ...     'sample_data.xls')
    >>> browser.getControl('Submit').click()

We should get an error:

    >>> browser.printQuery('//p[@class="error"]')
    <p class="error">Persons A3 Username cannot contain non-ascii characters: student00...</p>
    <p class="error">Persons A13 Username cannot contain non-ascii characters: student01...</p>
