Test coverage for schooltool.calendar

schooltool/      covered 77% (4766 of 21338 uncovered)
    calendar/      covered 98% (23 of 1341 uncovered)
        generate_vcal_dict.py      covered 69% (11 of 36 uncovered)
        mixins.py      covered 92% (7 of 92 uncovered)
        recurrent.py      covered 98% (4 of 360 uncovered)
        simple.py      covered 97% (1 of 44 uncovered)
        __init__.py      covered 100% (0 of 1 uncovered)
        browser.py      covered 100% (0 of 23 uncovered)
        icalendar.py      covered 100% (0 of 600 uncovered)
        interfaces.py      covered 100% (0 of 107 uncovered)
        utils.py      covered 100% (0 of 78 uncovered)