def test_concat(self):
        class ConcatFilter(Filter):
            def concat(self, out, hunks, **kw):
                out.write('%%%'.join([h.data() for h, info in hunks]))
        self.create_files({'a': '1', 'b': '2'})
        self.mkbundle('a', 'b', filters=ConcatFilter, output='out').build()
        assert self.get('out') == '1%%%2'

    # TODO: concat filter child bundle behavior: This should probably be
    # "special", i.e.  the parent concat filter is used, unless overridden
    # in the child.
Test the concat() filter type.
dataset/ETHPy150Open miracle2k/webassets/tests/test_bundle_build.py/TestFilterApplication.test_concat