Stop using PYTHONHASHSEED=0 in ceilometer tests

Otherwise we have tests that rely on ordering (for example the one
fixed in this patchset).

Note that this moves the hash seed setting to only be used in docs
and venv tox targets. For some reason there is an issue in the tooling
used by the docs build that tickles a bug in those tools. Tools which
are not part of Ceilometer. To avoid tickling the problem and to move
ceilometer along on this bug, we're just going to mask that.

The venv target is used by the jenkins job that builds docs. It runs
the same build_sphinx setup.py target that the docs target does.

Change-Id: If93ec7934ad59515b821f056ca534d3676ee7e03
Closes-Bug: #1348818

ceilometer/tests/api/v2/test_alarm_scenarios.py

@@ -914,9 +914,14 @@ class TestAlarms(v2.FunctionalTest,
                               status=400, headers=self.auth_headers)
         alarms = list(self.alarm_conn.get_alarms())
         self.assertEqual(7, len(alarms))
-        self.assertEqual('threshold_rule and combination_rule cannot '
-                         'be set at the same time',
-                         resp.json['error_message']['faultstring'])
+
+        # threshold_rule and combination_rule order is not
+        # predictable so it is not possible to do an exact match
+        # here
+        error_faultstring = resp.json['error_message']['faultstring']
+        for expected_string in ['threshold_rule', 'combination_rule',
+                                'cannot be set at the same time']:
+            self.assertIn(expected_string, error_faultstring)
 
     def test_post_invalid_alarm_timestamp_in_threshold_rule(self):
         date_time = datetime.datetime(2012, 7, 2, 10, 41)

tox.ini

@@ -10,7 +10,6 @@ install_command = pip install -U {opts} {packages}
 usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
          EVENTLET_NO_GREENDNS=yes
-         PYTHONHASHSEED=0
 commands =
    bash -x {toxinidir}/setup-test-env-mongodb.sh python setup.py testr --slowest --testr-args="{posargs}"
 downloadcache = {toxworkdir}/_download
@@ -72,12 +71,14 @@ commands =
 
 [testenv:docs]
 commands = python setup.py build_sphinx
+setenv = PYTHONHASHSEED=0
 
 [testenv:pylint]
 commands = bash tools/lintstack.sh
 
 [testenv:venv]
 commands = {posargs}
+setenv = PYTHONHASHSEED=0
 
 [testenv:debug]
 commands = bash -x {toxinidir}/setup-test-env-mongodb.sh oslo_debug_helper {posargs}