From: Gregory P. Smith <greg@krypto.org>
Date: Mon, 14 Dec 2015 04:01:44 +0000 (-0800)
Subject: Fix test_cmd_line not to fail if PYTHONHASHSEED is set to a fixed seed
X-Git-Tag: v3.6.0a1~912^2^2~2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=220ba72c20869975ee9e900f78c7a724db13a3ee;p=python

Fix test_cmd_line not to fail if PYTHONHASHSEED is set to a fixed seed
due to test_hash_randomization expecting a different seed per process.
---

diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index cb9bbddc8c..5cad3eca62 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -402,12 +402,24 @@ class CmdLineTest(unittest.TestCase):
         # Verify that -R enables hash randomization:
         self.verify_valid_flag('-R')
         hashes = []
-        for i in range(2):
+        if os.environ.get('PYTHONHASHSEED', 'random') != 'random':
+            env = dict(os.environ)  # copy
+            # We need to test that it is enabled by default without
+            # the environment variable enabling it for us.
+            del env['PYTHONHASHSEED']
+            env['__cleanenv'] = '1'  # consumed by assert_python_ok()
+        else:
+            env = {}
+        for i in range(3):
             code = 'print(hash("spam"))'
-            rc, out, err = assert_python_ok('-c', code)
+            rc, out, err = assert_python_ok('-c', code, **env)
             self.assertEqual(rc, 0)
             hashes.append(out)
-        self.assertNotEqual(hashes[0], hashes[1])
+        hashes = sorted(set(hashes))  # uniq
+        # Rare chance of failure due to 3 random seeds honestly being equal.
+        self.assertGreater(len(hashes), 1,
+                           msg='3 runs produced an identical random hash '
+                               ' for "spam": {}'.format(hashes))
 
         # Verify that sys.flags contains hash_randomization
         code = 'import sys; print("random is", sys.flags.hash_randomization)'