def METHOD_NAME(library, fw_pointers_cfg):
    with FwPointersCtx(fw_pointers_cfg):
        with patch('arctic.store._ndarray_store._CHUNK_SIZE', 1000):
            ndarr = np.random.rand(1024)
            library.write('MYARR', ndarr)
            saved_arr = library.read('MYARR').data
            assert np.all(ndarr == saved_arr)
            orig_chunks = mongo_count(library._collection)
            assert orig_chunks == 9
            # Concatenate more values
            ndarr = np.concatenate([ndarr, np.random.rand(10)])
            # And change the original values - we're not a simple append
            ndarr[0] = ndarr[1] = ndarr[2] = 0
            library.write('MYARR', ndarr)
            saved_arr = library.read('MYARR').data
            assert np.all(ndarr == saved_arr)
            # Should contain the original chunks, but not double the number
            # of chunks
            new_chunks = mongo_count(library._collection)
            assert new_chunks == 11
            if fw_pointers_cfg in (FwPointersCfg.DISABLED, FwPointersCfg.HYBRID):
                # We hit the update (rather than upsert) code path
                assert mongo_count(library._collection, filter={'parent': {'$size': 2}}) == 7
            if fw_pointers_cfg in (FwPointersCfg.HYBRID, FwPointersCfg.ENABLED):
                assert len(library._versions.find_one({'symbol': 'MYARR', 'version': 2})[FW_POINTERS_REFS_KEY]) == 9