Disable cron trigger thread for API unit tests

* API unit tests activated cron trigger thread whereas all unit tests
  assume that it's not started. Tests  where it needs to be activated
  should do it explicitly and shut down it after completion.
  This was causing unpredictable results where we were assuming that
  there weren't any active cron trigger threads.
* Minor cosmetic changes

Change-Id: I7e30f80b29520e03f2e1673788c764aabe1e4a8b
Closes-Bug: #1564353

mistral/api/app.py

@@ -45,13 +45,15 @@ def get_pecan_config():
 def setup_app(config=None):
     if not config:
         config = get_pecan_config()
+
     m_config.set_config_defaults()
 
     app_conf = dict(config.app)
 
     db_api_v2.setup_db()
 
-    periodic.setup()
+    if not app_conf.pop('disable_cron_trigger_thread', False):
+        periodic.setup()
 
     coordination.Service('api_group').register_membership()
 
@@ -67,6 +69,4 @@ def setup_app(config=None):
 
     # Create a CORS wrapper, and attach mistral-specific defaults that must be
     # included in all CORS responses.
-    app = cors_middleware.CORS(app, cfg.CONF)
-
-    return app
+    return cors_middleware.CORS(app, cfg.CONF)

mistral/tests/unit/api/base.py

@@ -20,6 +20,7 @@ import pecan
 import pecan.testing
 from webtest import app as webtest_app
 
+from mistral.services import periodic
 from mistral.tests.unit import base
 
 # Disable authentication for functional tests.
@@ -38,7 +39,8 @@ class FunctionalTest(base.DbTestCase):
                 'root': pecan_opts.root,
                 'modules': pecan_opts.modules,
                 'debug': pecan_opts.debug,
-                'auth_enable': False
+                'auth_enable': False,
+                'disable_cron_trigger_thread': True
             }
         })
 
@@ -48,6 +50,11 @@ class FunctionalTest(base.DbTestCase):
                         False,
                         group='pecan')
 
+        # Adding cron trigger thread clean up explicitly in case if
+        # new tests will provide an alternative configuration for pecan
+        # application.
+        self.addCleanup(periodic.stop_all_periodic_tasks)
+
         # Make sure the api get the correct context.
         self.patch_ctx = mock.patch('mistral.context.context_from_headers')
         self.mock_ctx = self.patch_ctx.start()

mistral/tests/unit/api/test_auth.py

@@ -66,12 +66,15 @@ class TestKeystoneMiddleware(base.FunctionalTest):
 
     def setUp(self):
         super(TestKeystoneMiddleware, self).setUp()
+
         cfg.CONF.set_default('auth_enable', True, group='pecan')
+
         self.app = pecan.testing.load_test_app({
             'app': {
                 'root': cfg.CONF.pecan.root,
                 'modules': cfg.CONF.pecan.modules,
                 'debug': cfg.CONF.pecan.debug,
-                'auth_enable': cfg.CONF.pecan.auth_enable
+                'auth_enable': cfg.CONF.pecan.auth_enable,
+                'disable_cron_trigger_thread': True
             }
         })

mistral/tests/unit/api/test_cors_middleware.py

@@ -20,12 +20,12 @@ from oslo_middleware import cors as cors_middleware
 
 
 class TestCORSMiddleware(base.FunctionalTest):
-    '''Provide a basic smoke test to ensure CORS middleware is active.
+    """Provide a basic smoke test to ensure CORS middleware is active.
 
     The tests below provide minimal confirmation that the CORS middleware
     is active, and may be configured. For comprehensive tests, please consult
     the test suite in oslo_middleware.
-    '''
+    """
 
     def setUp(self):
         # Make sure the CORS options are registered

mistral/tests/unit/services/test_trigger_service.py

@@ -288,9 +288,14 @@ class TriggerServiceV2Test(base.DbTestCase):
     @mock.patch.object(rpc.EngineClient, 'start_workflow')
     def test_single_execution_with_multiple_processes(self, start_wf_mock):
         def stop_thread_groups():
-            [tg.stop() for tg in self.triggers]
+            print('Killing cron trigger threads...')
+            [tg.stop() for tg in self.trigger_threads]
 
-        self.triggers = [periodic.setup(), periodic.setup(), periodic.setup()]
+        self.trigger_threads = [
+            periodic.setup(),
+            periodic.setup(),
+            periodic.setup()
+        ]
         self.addCleanup(stop_thread_groups)
 
         trigger_count = 5