Test coverage for schooltool.traverser

schooltool/      covered 72% (7525 of 27762 uncovered)
    traverser/      covered 92% (13 of 174 uncovered)
        metaconfigure.py      covered 80% (6 of 31 uncovered)
        traverser.py      covered 95% (4 of 99 uncovered)
        browser.py      covered 62% (3 of 8 uncovered)
        __init__.py      covered 100% (0 of 1 uncovered)
        interfaces.py      covered 100% (0 of 8 uncovered)
        metadirectives.py      covered 100% (0 of 27 uncovered)