diff --git a/tests/modelling/test_engine.py b/tests/modelling/test_engine.py
index fa82f4d0..da658d42 100644
--- a/tests/modelling/test_engine.py
+++ b/tests/modelling/test_engine.py
@@ -40,7 +40,6 @@ from zipline.data.ffc.loaders.us_equity_pricing import (
     USEquityPricingLoader,
 )
 from zipline.finance import trading
-from zipline.finance.trading import TradingEnvironment
 from zipline.modelling.engine import SimpleFFCEngine
 from zipline.modelling.factor import TestingFactor
 from zipline.modelling.factor.technical import (
diff --git a/tests/test_algorithm.py b/tests/test_algorithm.py
index 8460613f..e27b1a6c 100644
--- a/tests/test_algorithm.py
+++ b/tests/test_algorithm.py
@@ -23,7 +23,6 @@ from unittest import TestCase
 import numpy as np
 import pandas as pd
 
-from zipline.assets import AssetFinder
 from zipline.utils.api_support import ZiplineAPI
 from zipline.utils.control_flow import nullctx
 from zipline.utils.test_utils import (
diff --git a/tests/test_blotter.py b/tests/test_blotter.py
index ebd36498..81186139 100644
--- a/tests/test_blotter.py
+++ b/tests/test_blotter.py
@@ -19,7 +19,6 @@ from unittest import TestCase
 
 from zipline.finance import trading
 from zipline.finance.blotter import Blotter, ORDER_STATUS
-from zipline.finance.trading import with_environment
 from zipline.finance.execution import (
     LimitOrder,
     MarketOrder,
diff --git a/tests/test_perf_tracking.py b/tests/test_perf_tracking.py
index f4468ced..f95f4421 100644
--- a/tests/test_perf_tracking.py
+++ b/tests/test_perf_tracking.py
@@ -34,7 +34,6 @@ import pandas as pd
 import numpy as np
 from six.moves import range, zip
 
-from zipline.assets import AssetFinder
 import zipline.utils.factory as factory
 import zipline.finance.performance as perf
 from zipline.finance.slippage import Transaction, create_transaction
diff --git a/zipline/assets/asset_writer.py b/zipline/assets/asset_writer.py
index bc5688db..d3484432 100644
--- a/zipline/assets/asset_writer.py
+++ b/zipline/assets/asset_writer.py
@@ -325,9 +325,6 @@ class AssetDBWriter(with_metaclass(ABCMeta)):
         equities_output['first_traded'] = \
             equities_output['first_traded'].apply(self.convert_datetime)
 
-        # Convert symbols to upper case.
-        equities_output['symbol'] = equities_output.symbol.str.upper()
-
         # ******** Generate futures data ********
 
         futures_defaults = {
diff --git a/zipline/sources/simulated.py b/zipline/sources/simulated.py
index e25a429b..8fd65806 100644
--- a/zipline/sources/simulated.py
+++ b/zipline/sources/simulated.py
@@ -23,7 +23,6 @@ import pandas as pd
 from zipline.sources.data_source import DataSource
 from zipline.utils import tradingcalendar as calendar_nyse
 from zipline.gens.utils import hash_args
-from zipline.finance.trading import TradingEnvironment
 
 
 class RandomWalkSource(DataSource):