    def test_data_collection_filter(self):
        """
        target: test filter() API for pipeline
        method: Get the input data, apply it to a function, check the function
                with filter_columns,then output.
        expected: output successfully
        """
        p = towhee.pipe.input('a').filter('a', 'a', 'a', lambda x: x > 10).output('a')
        assert p(1).get() is None
        assert p(11).get() == [11]

        # The order of filter() and map() can't be reversed here!
        q = towhee.pipe.input('a').filter('a', 'a', 'a', lambda x: x > 10)\
                                  .map('a', 'b', lambda x: x + 1).output('b')
        assert q(5).get() is None
        assert q(20).get() == [21]
        return True
target: test filter() API for pipeline
method: Get the input data, apply it to a function, check the function
with filter_columns,then output.
expected: output successfully
tests/testcases/test_data_collection.py