問題描述

我在 Python2 中有這個(gè)代碼段:

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

我想為其編寫一些單元測(cè)試.我想知道如何使用 mock.patch 來修補(bǔ)游標(biāo)和連接變量，以便它們返回一組假數(shù)據(jù)?我已經(jīng)為我的單元測(cè)試嘗試了以下代碼段，但無(wú)濟(jì)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()

但我似乎收到以下錯(cuò)誤:

But I seem to get the following error:

TypeError: can't set attributes of built-in/extension type 'psycopg2.extensions.cursor'

推薦答案

由于游標(biāo)是con.cursor的返回值，所以只需要mock連接，然后正確配置即可.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()

這篇關(guān)于如何模擬 psycopg2 光標(biāo)對(duì)象?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！