SA14/Tests: Adjust DialectTest mechanics to mitigate weird NPE

Croaks otherwise::

      File "/path/to/site-packages/sqlalchemy/testing/assertions.py", line 301, in in_
        assert a in b, msg or "%r not in %r" % (a, b)

    TypeError: argument of type 'NoneType' is not iterable

Now, this test case uses the same way to provide a fake Cursor instance
like the others. However, there is a special requirement here that the
fake Cursor should set `self.executed_statement`, when invoked.

So, providing the fake cursor is done through a wrapper function,
patching the corresponding `.execute()` methods, like before.

Author: amotl

src/crate/client/sqlalchemy/tests/dialect_test.py

@@ -21,31 +21,42 @@
 
 from datetime import datetime
 from unittest import TestCase
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
 import sqlalchemy as sa
+
+from crate.client.cursor import Cursor
+from crate.client.sqlalchemy.sa_version import SA_VERSION, SA_1_4
 from crate.client.sqlalchemy.types import Object
 from sqlalchemy import inspect
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import Session
 from sqlalchemy.testing import eq_, in_
 
 fake_cursor = MagicMock(name='fake_cursor')
+FakeCursor = MagicMock(name='FakeCursor', spec=Cursor)
+FakeCursor.return_value = fake_cursor
 
 
+@patch('crate.client.connection.Cursor', FakeCursor)
 class DialectTest(TestCase):
 
+    def execute_wrapper(self, query, *args, **kwargs):
+        self.executed_statement = query
+        return fake_cursor
+
     def setUp(self):
         self.engine = sa.create_engine('crate://')
         self.executed_statement = None
 
-        def execute_wrapper(query, *args, **kwargs):
-            self.executed_statement = query
-            return fake_cursor
-
-        self.engine.execute = execute_wrapper
         self.connection = self.engine.connect()
-        self.connection.execute = execute_wrapper
+
+        if SA_VERSION < SA_1_4:
+            self.engine.execute = self.execute_wrapper
+            self.connection.execute = self.execute_wrapper
+        else:
+            fake_cursor.execute = self.execute_wrapper
+
         self.base = declarative_base(bind=self.engine)
 
         class Character(self.base):