diff --git a/tests/test_algorithm.py b/tests/test_algorithm.py
index b0c132d3..bc82f310 100644
--- a/tests/test_algorithm.py
+++ b/tests/test_algorithm.py
@@ -101,6 +101,9 @@ from zipline.protocol import DATASOURCE_TYPE
 from zipline.finance.trading import TradingEnvironment
 from zipline.finance.commission import PerShare
 
+# Because test cases appear to reuse some resources.
+_multiprocess_can_split_ = False
+
 
 class TestRecordAlgorithm(TestCase):
     def setUp(self):
diff --git a/tests/test_examples.py b/tests/test_examples.py
index 39e0d4bd..38474471 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -26,6 +26,9 @@ from nose_parameterized import parameterized
 import os
 from unittest import TestCase
 
+# Otherwise the next line sometimes complains about being run too late.
+_multiprocess_can_split_ = False
+
 matplotlib.use('Agg')