diff --git a/tests/test_history.py b/tests/test_history.py
index ab242661..8bc3842d 100644
--- a/tests/test_history.py
+++ b/tests/test_history.py
@@ -22,7 +22,7 @@ import numpy as np
 import pandas as pd
 from pandas.util.testing import assert_frame_equal
 
-from zipline.history import history, Frequency
+from zipline.history import history
 from zipline.history.history_container import HistoryContainer
 from zipline.protocol import BarData
 import zipline.utils.factory as factory
diff --git a/zipline/history/history_container.py b/zipline/history/history_container.py
index e61d38d9..a71a52a6 100644
--- a/zipline/history/history_container.py
+++ b/zipline/history/history_container.py
@@ -594,7 +594,7 @@ class HistoryContainer(object):
         )
         self.buffer_spec = spec
 
-        if bar_data:
+        if bar_data is not None:
             frame = self.frame_from_bardata(bar_data, initial_dt)
             rp.add_frame(initial_dt, frame)