diff --git a/tests/test_security_list.py b/tests/test_security_list.py
index 7827ffce..8596444d 100644
--- a/tests/test_security_list.py
+++ b/tests/test_security_list.py
@@ -7,7 +7,7 @@ from zipline.algorithm import TradingAlgorithm
 from zipline.errors import TradingControlViolation
 from zipline.sources import SpecificEquityTrades
 from zipline.utils.test_utils import (
-    setup_logger, add_security_data, remove_security_data_directory)
+    setup_logger, security_list_copy, add_security_data)
 from zipline.utils import factory
 from zipline.utils.security_list import (
     SecurityListSet, load_from_directory)
@@ -105,26 +105,22 @@ class SecurityListTestCase(TestCase):
     def test_security_add(self):
         def get_datetime():
             return datetime(2015, 1, 27, tzinfo=pytz.utc)
-        try:
+        with security_list_copy():
             add_security_data(['AAPL', 'GOOG'], [])
             rl = SecurityListSet(get_datetime)
             self.assertIn("AAPL", rl.leveraged_etf_list)
             self.assertIn("GOOG", rl.leveraged_etf_list)
             self.assertIn("BZQ", rl.leveraged_etf_list)
             self.assertIn("URTY", rl.leveraged_etf_list)
-        finally:
-            remove_security_data_directory()
 
     def test_security_add_delete(self):
-        try:
+        with security_list_copy():
             def get_datetime():
                 return datetime(2015, 1, 27, tzinfo=pytz.utc)
             add_security_data([], ['BZQ', 'URTY'])
             rl = SecurityListSet(get_datetime)
             self.assertNotIn("BZQ", rl.leveraged_etf_list)
             self.assertNotIn("URTY", rl.leveraged_etf_list)
-        finally:
-            remove_security_data_directory()
 
     def test_algo_without_rl_violation_via_check(self):
         sim_params = factory.create_simulation_parameters(
@@ -228,7 +224,7 @@ class SecurityListTestCase(TestCase):
             start=list(
                 LEVERAGED_ETFS.keys())[0] + timedelta(days=7), num_days=4)
 
-        try:
+        with security_list_copy():
             add_security_data(['AAPL'], [])
             trade_history = factory.create_trade_history(
                 'BZQ',
@@ -244,11 +240,9 @@ class SecurityListTestCase(TestCase):
                 algo.run(self.source)
 
             self.check_algo_exception(algo, ctx, 0)
-        finally:
-            remove_security_data_directory()
 
     def test_algo_without_rl_violation_after_delete(self):
-        try:
+        with security_list_copy():
             # add a delete statement removing bzq
             # write a new delete statement file to disk
             add_security_data([], ['BZQ'])
@@ -266,11 +260,9 @@ class SecurityListTestCase(TestCase):
             algo = RestrictedAlgoWithoutCheck(
                 sid='BZQ', sim_params=sim_params)
             algo.run(self.source)
-        finally:
-            remove_security_data_directory()
 
     def test_algo_with_rl_violation_after_add(self):
-        try:
+        with security_list_copy():
             add_security_data(['AAPL'], [])
             sim_params = factory.create_simulation_parameters(
                 start=self.trading_day_before_first_kd, num_days=4)
@@ -288,8 +280,6 @@ class SecurityListTestCase(TestCase):
                 algo.run(self.source)
 
             self.check_algo_exception(algo, ctx, 2)
-        finally:
-            remove_security_data_directory()
 
     def check_algo_exception(self, algo, ctx, expected_order_count):
         self.assertEqual(algo.order_count, expected_order_count)
diff --git a/zipline/utils/test_utils.py b/zipline/utils/test_utils.py
index 75faff62..fb217edf 100644
--- a/zipline/utils/test_utils.py
+++ b/zipline/utils/test_utils.py
@@ -1,13 +1,15 @@
 from contextlib import contextmanager
 from logbook import FileHandler
+from mock import patch
 from zipline.finance.blotter import ORDER_STATUS
-from zipline.utils.security_list import SECURITY_LISTS_DIR
+from zipline.utils import security_list
 
 from six import itervalues
 
 import os
 import pandas as pd
 import shutil
+import tempfile
 
 
 def to_utc(time_str):
@@ -115,15 +117,34 @@ def nullctx():
     Null context manager.  Useful for conditionally adding a contextmanager in
     a single line, e.g.:
 
-    with SomeContextManager() if some_expr else nullcontext:
+    with SomeContextManager() if some_expr else nullctx():
         do_stuff()
     """
     yield
 
 
+@contextmanager
+def security_list_copy():
+    old_dir = security_list.SECURITY_LISTS_DIR
+    new_dir = tempfile.mkdtemp()
+    try:
+        for subdir in os.listdir(old_dir):
+            shutil.copytree(os.path.join(old_dir, subdir),
+                            os.path.join(new_dir, subdir))
+            with patch.object(security_list, 'SECURITY_LISTS_DIR', new_dir), \
+                    patch.object(security_list, 'using_copy', True,
+                                 create=True):
+                yield
+    finally:
+        shutil.rmtree(new_dir, True)
+
+
 def add_security_data(adds, deletes):
+    if not hasattr(security_list, 'using_copy'):
+        raise Exception('add_security_data must be used within '
+                        'security_list_copy context')
     directory = os.path.join(
-        SECURITY_LISTS_DIR,
+        security_list.SECURITY_LISTS_DIR,
         "leveraged_etf_list/20150127/20150125"
     )
     if not os.path.exists(directory):
@@ -138,11 +159,3 @@ def add_security_data(adds, deletes):
         for sym in adds:
             f.write(sym)
             f.write('\n')
-
-
-def remove_security_data_directory():
-    directory = os.path.join(
-        SECURITY_LISTS_DIR,
-        "leveraged_etf_list/20150127/"
-    )
-    shutil.rmtree(directory)