diff -r 7046ecabd9a8 -r 031947baf4d0 tests/sitecustomize.py
--- a/tests/sitecustomize.py	Fri Mar 27 23:17:19 2015 -0700
+++ b/tests/sitecustomize.py	Sat Mar 28 00:47:58 2015 -0700
@@ -1,5 +1,16 @@
-try:
-    import coverage
-    getattr(coverage, 'process_startup', lambda: None)()
-except ImportError:
-    pass
+import os
+
+if os.environ.get('COVERAGE_PROCESS_START'):
+    try:
+        import coverage
+        import random
+
+        # uuid is better, but not available in Python 2.4.
+        covpath = os.path.join(os.environ['COVERAGE_DIR'],
+                               'cov.%s' % random.randrange(0, 1000000000000))
+        cov = coverage.coverage(data_file=covpath, auto_data=True)
+        cov._warn_no_data = False
+        cov._warn_unimported_source = False
+        cov.start()
+    except ImportError:
+        pass