Python3: fix test_stack_list_with_args()

The expected_url in test_stack_list_with_args() does not always match the URL
actually used in the code. This patch fixes this issue by:
- using urlutils.urlencode() in both the code and the tests, so that changes in
 the urlencode() implementation do not affect the tests;
- setting the PYTHONHASHSEED environment variable to 0 when running the tests,
  so that randomisation is disabled and urlutils.urlencode() has predictable
  results.

Change-Id: I5b50bad98f5c237cdc12e4ab75f21917ca0ef30d

heatclient/tests/test_shell.py

@@ -392,9 +392,11 @@ class ShellTestUserPass(ShellBase):
 
     def test_stack_list_with_args(self):
         self._script_keystone_client()
-        expected_url = ('/stacks?'
-                        'status=COMPLETE&status=FAILED'
-                        '&marker=fake_id&limit=2')
+        expected_url = '/stacks?%s' % urlutils.urlencode({
+            'limit': 2,
+            'status': ['COMPLETE', 'FAILED'],
+            'marker': 'fake_id',
+        }, True)
         fakes.script_heat_list(expected_url)
 
         self.m.ReplayAll()

tox.ini

@@ -4,7 +4,10 @@ minversion = 1.6
 skipsdist = True
 
 [testenv]
+# Set PYTHONHASHSEED to 0 so that randomisation is disabled and
+# urlutils.urlencode() has predictable results.
 setenv = VIRTUAL_ENV={envdir}
+        PYTHONHASHSEED=0
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt