Fix the ServiceUnavailable test.

Author: srbaker

test/examples/service_unavailable_example.py

@@ -29,10 +29,10 @@ def __init__(self, uri, user, password):
 
     # tag::service-unavailable[]
     def addItem(self):
+        session = self._driver.session()
         try:
-            with self._driver.session() as session:
-                session.write_transaction(lambda tx: tx.run("CREATE (a:Item)"))
-                return True
+            session.write_transaction(lambda tx: tx.run("CREATE (a:Item)"))
+            return True
         except ServiceUnavailable as e:
             return False
     # end::service-unavailable[]

test/examples/test_examples.py

@@ -110,11 +110,11 @@ def test_service_unavailable_example(self):
         from service_unavailable_example import ServiceUnavailableExample
 
         example = ServiceUnavailableExample(self.bolt_uri, self.user, self.password)
-        ExamplesTest._stop_server()
+        ExamplesTest.controller.stop()
 
         self.assertFalse(example.addItem())
 
-        ExamplesTest._start_server()
+        ExamplesTest.controller.start()
 
     def test_session_example(self):
         from session_example import SessionExample