Convert some unittests to pytest. (#2779)

* Convert multi_node_test.py to pytest.

* Convert array_test.py to pytest.

* Convert failure_test.py to pytest.

* Convert microbenchmarks to pytest.

* Convert component_failures_test.py to pytest and some minor quotes changes.

* Convert tensorflow_test.py to pytest.

* Convert actor_test.py to pytest.

* Fix.

* Fix

Author: robertnishihara

python/ray/global_scheduler/test/test.py

@@ -189,7 +189,7 @@ def test_redis_only_single_task(self):
         assert (db_client_id is not None)
 
     @unittest.skipIf(
-        os.environ.get('RAY_USE_NEW_GCS', False),
+        os.environ.get("RAY_USE_NEW_GCS", False),
         "New GCS API doesn't have a Python API yet.")
     def test_integration_single_task(self):
         # There should be three db clients, the global scheduler, the local
@@ -307,13 +307,13 @@ def integration_many_tasks_helper(self, timesync=True):
         self.assertEqual(num_tasks_done + num_tasks_waiting, num_tasks)
 
     @unittest.skipIf(
-        os.environ.get('RAY_USE_NEW_GCS', False),
+        os.environ.get("RAY_USE_NEW_GCS", False),
         "New GCS API doesn't have a Python API yet.")
     def test_integration_many_tasks_handler_sync(self):
         self.integration_many_tasks_helper(timesync=True)
 
     @unittest.skipIf(
-        os.environ.get('RAY_USE_NEW_GCS', False),
+        os.environ.get("RAY_USE_NEW_GCS", False),
         "New GCS API doesn't have a Python API yet.")
     def test_integration_many_tasks(self):
         # More realistic case: should handle out of order object and task