ENH: Add single-column input/output capabilities to pipeline terms

zipline/testing/__init__.py

@@ -1,9 +1,12 @@
 from .core import (  # noqa
+    AssetID,
+    AssetIDPlusDay,
     EPOCH,
     ExplodingObject,
     FakeDataPortal,
     FetcherDataPortal,
     MockDailyBarReader,
+    OpenPrice,
     add_security_data,
     all_pairs_matching_predicate,
     all_subindices,
@@ -22,6 +25,8 @@ from .core import (  # noqa
     empty_asset_finder,
     empty_assets_db,
     empty_trading_env,
+    make_alternating_boolean_array,
+    make_cascading_boolean_array,
     make_test_handler,
     make_trade_data_for_asset_info,
     parameter_space,