* Re-fix issue #19284: Don't generate the no-op -R command line

parameter to "enable" the always on sys.flags.hash_randomization
  in _args_from_interpreter_flags() used by multiprocessing and
  some unittests.  This simplifies the code.
* assert_python_ok docstring typo fix.
* Fix test_cmd_line not to fail if PYTHONHASHSEED is set to a fixed seed.

Lib/subprocess.py

@@ -535,14 +535,11 @@ def _args_from_interpreter_flags():
         'verbose': 'v',
         'bytes_warning': 'b',
         'quiet': 'q',
-        'hash_randomization': 'R',
     }
     args = []
     for flag, opt in flag_opt_map.items():
         v = getattr(sys.flags, flag)
         if v > 0:
-            if flag == 'hash_randomization':
-                v = 1 # Handle specification of an exact seed
             args.append('-' + opt * v)
     for opt in sys.warnoptions:
         args.append('-W' + opt)

Lib/test/support/script_helper.py

@@ -127,7 +127,7 @@ def assert_python_ok(*args, **env_vars):
     variables `env_vars` succeeds (rc == 0) and return a (return code, stdout,
     stderr) tuple.
 
-    If the __cleanenv keyword is set, env_vars is used a fresh environment.
+    If the __cleanenv keyword is set, env_vars is used as a fresh environment.
 
     Python is started in isolated mode (command line option -I),
     except if the __isolated keyword is set to False.

Lib/test/test_cmd_line.py

@@ -403,12 +403,24 @@ 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)'