def test_simple_bundle(self):
        self.mkbundle('in1', 'in2', output='out').build()
        assert self.get('out') == 'A\nB'
Return a count of messages in the mailbox.
dataset/ETHPy150Open miracle2k/webassets/tests/test_bundle_build.py/TestBuildVarious.test_simple_bundle--crossover with--dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/Maildir.__len__