问题描述
我在 Python2 中有这个代码段:
I have this code segment in Python2:
def super_cool_method(): con = psycopg2.connect(**connection_stuff) cur = con.cursor(cursor_factory=DictCursor) cur.execute("Super duper SQL query") rows = cur.fetchall() for row in rows: # do some data manipulation on row return rows
我想为其编写一些单元测试.我想知道如何使用 mock.patch 来修补游标和连接变量,以便它们返回一组假数据?我已经为我的单元测试尝试了以下代码段,但无济于事:
that I'd like to write some unittests for. I'm wondering how to use mock.patch in order to patch out the cursor and connection variables so that they return a fake set of data? I've tried the following segment of code for my unittests but to no avail:
@mock.patch("psycopg2.connect") @mock.patch("psycopg2.extensions.cursor.fetchall") def test_super_awesome_stuff(self, a, b): testing = super_cool_method()
但我似乎收到以下错误:
But I seem to get the following error:
TypeError: can't set attributes of built-in/extension type 'psycopg2.extensions.cursor'
推荐答案
由于游标是con.cursor的返回值,所以只需要mock连接,然后正确配置即可.例如,
Since the cursor is the return value of con.cursor, you only need to mock the connection, then configure it properly. For example,
query_result = [("field1a", "field2a"), ("field1b", "field2b")] with mock.patch('psycopg2.connect') as mock_connect: mock_connect.cursor.return_value.fetchall.return_value = query_result super_cool_method()