Test more engine types in argument passing unit test

Change-Id: I8cdca39b488fecef495a501640a1b2c7efaf6b79

taskflow/tests/unit/test_arguments_passing.py

@@ -14,10 +14,14 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import testtools
+
 import taskflow.engines
 from taskflow import exceptions as exc
 from taskflow import test
 from taskflow.tests import utils
+from taskflow.types import futures
+from taskflow.utils import eventlet_utils as eu
 
 
 class ArgumentsPassingTest(utils.EngineTestBase):
@@ -160,8 +164,8 @@ class ArgumentsPassingTest(utils.EngineTestBase):
         })
 
 
-class SingleThreadedEngineTest(ArgumentsPassingTest,
-                               test.TestCase):
+class SerialEngineTest(ArgumentsPassingTest, test.TestCase):
+
     def _make_engine(self, flow, flow_detail=None):
         return taskflow.engines.load(flow,
                                      flow_detail=flow_detail,
@@ -169,10 +173,43 @@ class SingleThreadedEngineTest(ArgumentsPassingTest,
                                      backend=self.backend)
 
 
-class MultiThreadedEngineTest(ArgumentsPassingTest,
-                              test.TestCase):
+class ParallelEngineWithThreadsTest(ArgumentsPassingTest, test.TestCase):
+    _EXECUTOR_WORKERS = 2
+
     def _make_engine(self, flow, flow_detail=None, executor=None):
-        return taskflow.engines.load(flow, flow_detail=flow_detail,
+        if executor is None:
+            executor = 'threads'
+        return taskflow.engines.load(flow,
+                                     flow_detail=flow_detail,
                                      engine='parallel',
                                      backend=self.backend,
+                                     executor=executor,
+                                     max_workers=self._EXECUTOR_WORKERS)
+
+
+@testtools.skipIf(not eu.EVENTLET_AVAILABLE, 'eventlet is not available')
+class ParallelEngineWithEventletTest(ArgumentsPassingTest, test.TestCase):
+
+    def _make_engine(self, flow, flow_detail=None, executor=None):
+        if executor is None:
+            executor = futures.GreenThreadPoolExecutor()
+            self.addCleanup(executor.shutdown)
+        return taskflow.engines.load(flow,
+                                     flow_detail=flow_detail,
+                                     backend=self.backend,
+                                     engine='parallel',
                                      executor=executor)
+
+
+class ParallelEngineWithProcessTest(ArgumentsPassingTest, test.TestCase):
+    _EXECUTOR_WORKERS = 2
+
+    def _make_engine(self, flow, flow_detail=None, executor=None):
+        if executor is None:
+            executor = 'processes'
+        return taskflow.engines.load(flow,
+                                     flow_detail=flow_detail,
+                                     backend=self.backend,
+                                     engine='parallel',
+                                     executor=executor,
+                                     max_workers=self._EXECUTOR_WORKERS)