pyvows teardown not invoked unless all tests pass

gistfile1.py

from pyvows import Vows, expect

@Vows.batch
class IfATestFails(Vows.Context):
    def topic(self):
        return "oh noes!"

    def setup(self):
        print "test 1 setup: this will be printed"

    def teardown(self):
        print "test 2 teardown: this will not be printed - oh noes!"

    def the_teardown_method_never_gets_called(self, topic):
        expect(topic).to_equal(42)

@Vows.batch
class IfAllTestsPass(Vows.Context):
    def topic(self):
        return True

    def setup(self):
        print "test 2 setup: this will be printed"

    def teardown(self):
        print "test 2 teardown: this will be printed"

    def the_teardown_method_gets_called(self, topic):
        expect(topic).to_be_true()