Run some engine tests with eventlet if it's available

This change adds test cases that run some of engine tests against
parallel engine with GreenExecutor if eventlet is available, in addition
to current tests for single-threaded engine and parallel engine with
native threading executor.

Change-Id: I7be6de9a80034b7363fb9e0680d63090a05d1c12

taskflow/tests/unit/test_action_engine.py

@@ -18,6 +18,7 @@
 
 import contextlib
 import networkx
+import testtools
 
 from concurrent import futures
 
@@ -34,6 +35,8 @@ from taskflow import states
 from taskflow import task
 from taskflow import test
 from taskflow.tests import utils
+
+from taskflow.utils import eventlet_utils as eu
 from taskflow.utils import misc
 from taskflow.utils import persistence_utils as p_utils
 
@@ -606,3 +609,20 @@ class MultiThreadedEngineTest(EngineTaskTest,
             self.assertIs(e1.executor, e2.executor)
         finally:
             executor.shutdown(wait=True)
+
+
+@testtools.skipIf(not eu.EVENTLET_AVAILABLE, 'eventlet is not available')
+class ParallelEngineWithEventletTest(EngineTaskTest,
+                                     EngineLinearFlowTest,
+                                     EngineParallelFlowTest,
+                                     EngineGraphFlowTest,
+                                     test.TestCase):
+
+    def _make_engine(self, flow, flow_detail=None, executor=None):
+        if executor is None:
+            executor = eu.GreenExecutor()
+        engine_conf = dict(engine='parallel',
+                           executor=executor)
+        return taskflow.engines.load(flow, flow_detail=flow_detail,
+                                     engine_conf=engine_conf,
+                                     backend=self.backend)

taskflow/tests/unit/test_suspend_flow.py

@@ -16,9 +16,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import testtools
 import time
 
 from taskflow.patterns import linear_flow as lf
+from taskflow.utils import eventlet_utils as eu
 
 import taskflow.engines
 
@@ -222,3 +224,17 @@ class MultiThreadedEngineTest(SuspendFlowTest,
         return taskflow.engines.load(flow, flow_detail=flow_detail,
                                      engine_conf=engine_conf,
                                      backend=self.backend)
+
+
+@testtools.skipIf(not eu.EVENTLET_AVAILABLE, 'eventlet is not available')
+class ParallelEngineWithEventletTest(SuspendFlowTest,
+                                     test.TestCase):
+
+    def _make_engine(self, flow, flow_detail=None, executor=None):
+        if executor is None:
+            executor = eu.GreenExecutor()
+        engine_conf = dict(engine='parallel',
+                           executor=executor)
+        return taskflow.engines.load(flow, flow_detail=flow_detail,
+                                     engine_conf=engine_conf,
+                                     backend=self.backend)