refactor: update and document Cursor.executemany() method, add unit t… (#517)

Author: Ilya Gurov

google/cloud/spanner_dbapi/cursor.py

@@ -208,10 +208,7 @@ def __enter__(self):
         return self
 
     def __exit__(self, etype, value, traceback):
-        self.__clear()
-
-    def __clear(self):
-        self._connection = None
+        self.close()
 
     @property
     def description(self):
@@ -264,12 +261,20 @@ def close(self):
 
         The cursor will be unusable from this point forward.
         """
-        self.__clear()
         self._is_closed = True
 
     def executemany(self, operation, seq_of_params):
-        if not self._connection:
-            raise ProgrammingError("Cursor is not connected to the database")
+        """
+        Execute the given SQL with every parameters set
+        from the given sequence of parameters.
+
+        :type operation: :class:`str`
+        :param operation: SQL code to execute.
+
+        :type seq_of_params: :class:`list`
+        :param seq_of_params: Sequence of params to run the query with.
+        """
+        self._raise_if_closed()
 
         for params in seq_of_params:
             self.execute(operation, params)

tests/spanner_dbapi/test_cursor.py

@@ -52,3 +52,46 @@ def test_connection_closed(self):
         self.assertTrue(cursor.is_closed)
         with self.assertRaises(InterfaceError):
             cursor.execute("SELECT * FROM database")
+
+    def test_executemany_on_closed_cursor(self):
+        with mock.patch(
+            "google.cloud.spanner_v1.instance.Instance.exists",
+            return_value=True,
+        ):
+            with mock.patch(
+                "google.cloud.spanner_v1.database.Database.exists",
+                return_value=True,
+            ):
+                connection = connect("test-instance", "test-database")
+
+        cursor = connection.cursor()
+        cursor.close()
+
+        with self.assertRaises(InterfaceError):
+            cursor.executemany(
+                """SELECT * FROM table1 WHERE "col1" = @a1""", ()
+            )
+
+    def test_executemany(self):
+        operation = """SELECT * FROM table1 WHERE "col1" = @a1"""
+        params_seq = ((1,), (2,))
+
+        with mock.patch(
+            "google.cloud.spanner_v1.instance.Instance.exists",
+            return_value=True,
+        ):
+            with mock.patch(
+                "google.cloud.spanner_v1.database.Database.exists",
+                return_value=True,
+            ):
+                connection = connect("test-instance", "test-database")
+
+        cursor = connection.cursor()
+        with mock.patch(
+            "google.cloud.spanner_dbapi.cursor.Cursor.execute"
+        ) as execute_mock:
+            cursor.executemany(operation, params_seq)
+
+        execute_mock.assert_has_calls(
+            (mock.call(operation, (1,)), mock.call(operation, (2,)))
+        )