'Check if test is below base in a URI tree
Both args must be URIs in reduced form.'

def is_suburi(self, base, test):

    if (base == test):
        return True
    if (base[0] != test[0]):
        return False
    common = posixpath.commonprefix((base[1], test[1]))
    if (len(common) == len(base[1])):
        return True
    return False
