Revert "RM-96 fix vertica driver test"

This reverts commit 3581ff6.

tests/unit/db/vertica/test_vertica_db_driver.py

@@ -1,5 +1,5 @@
 from .base_test_vertica_db_driver import BaseTestVerticaDBDriver
-from mock import Mock
+from mock import Mock, MagicMock
 from ...records.format_hints import (vertica_format_hints)
 import sqlalchemy
 
@@ -8,7 +8,10 @@ class TestVerticaDBDriver(BaseTestVerticaDBDriver):
     def test_unload(self):
         mock_result = Mock(name='result')
         mock_result.rows = 579
-        self.mock_db_engine.execute.return_value.fetchall.return_value = [mock_result]
+        mock_connection = MagicMock(name='connection')
+        self.mock_db_engine.connect.return_value \
+            .__enter__.return_value = mock_connection
+        mock_connection.execute.return_value.fetchall.return_value = [mock_result]
         self.mock_records_unload_plan.processing_instructions.fail_if_dont_understand = True
         self.mock_records_unload_plan.processing_instructions.fail_if_cant_handle_hint = True
 
@@ -25,7 +28,10 @@ def test_unload(self):
     def test_unload_to_non_s3(self):
         mock_result = Mock(name='result')
         mock_result.rows = 579
-        self.mock_db_engine.execute.return_value.fetchall.return_value = [mock_result]
+        mock_connection = MagicMock(name='connection')
+        self.mock_db_engine.connect.return_value \
+            .__enter__.return_value = mock_connection
+        mock_connection.execute.return_value.fetchall.return_value = [mock_result]
         self.mock_records_unload_plan.processing_instructions.fail_if_dont_understand = True
         self.mock_records_unload_plan.processing_instructions.fail_if_cant_handle_hint = True