[英]Unittest.mock - how to mock a call to cursor.execute() from connection object?
我正在嘗試使用模擬在以下代碼中存根 cursor.execute() 以便我可以測試使用格式正確的查詢調用 execute :
// Module ABC
def buildAndExecuteQuery( tablesAndColumnsToSelect ):
'''Build and execute a query.
Args: tablesAndColumnsToSelect (dict)
- keys are table names, values are columns
'''
query = ..... < logic to build query > ....
from django.db import connections
cursor = connections[ 'mydb' ].cursor()
cursor.execute( query )
如何使用模擬庫在 python2.7 中完成這種類型的模擬?
我將用例子擴展@G_M 答案,因為我有兩個反對意見:
mock
我們不應該在定義對象的地方修補它們:基本原則是在查找對象的位置打補丁,該位置不一定與定義的位置相同。 幾個例子將有助於澄清這一點。
參考: https : //docs.python.org/3/library/unittest.mock.html#where-to-patch
例子:
我們要測試的函數:
# foooo_bar.py
from typing import Optional
from django.db import DEFAULT_DB_ALIAS, connections
def some_function(some_arg: str, db_alias: Optional[str] = DEFAULT_DB_ALIAS):
with connections[db_alias].cursor() as cursor:
cursor.execute('SOME SQL FROM %s;', [some_arg])
測試:
# test_foooo_bar.py
from unittest import mock
from django.db import DEFAULT_DB_ALIAS
from django.test import SimpleTestCase
from core.db_utils.xx import some_function
class ExampleSimpleTestCase(SimpleTestCase):
@mock.patch('foooo_bar.connections')
def test_some_function_executes_some_sql(self, mock_connections):
mock_cursor = mock_connections.__getitem__(DEFAULT_DB_ALIAS).cursor.return_value.__enter__.return_value
some_function('fooo')
# Demonstrating assert_* options:
mock_cursor.execute.assert_called_once()
mock_cursor.execute.assert_called()
mock_cursor.execute.assert_called_once_with('SOME SQL FROM %s;', ['fooo'])
由於我不知道您的查詢邏輯是什么,我將query
修改為僅通過tables_and_columns_to_select
參數直接接受哨兵值。
# b_and_ex_q.py
def build_and_execute_query(tables_and_columns_to_select):
"""Build and execute a query.
Args: tablesAndColumnsToSelect (dict)
- keys are table names, values are columns
"""
query = tables_and_columns_to_select # ..... < logic to build query > ....
from django.db import connections
cursor = connections['mydb'].cursor()
cursor.execute(query)
import unittest
from mock import patch, sentinel
from b_and_ex_q import build_and_execute_query
class TestCursorExecute(unittest.TestCase):
@patch('django.db.connections')
def test_build_and_execute_query(self, mock_connections):
# Arrange
mock_cursor = mock_connections.__getitem__('mydb').cursor.return_value
# Act
build_and_execute_query(sentinel.t_and_c)
# Assert
mock_cursor.execute.assert_called_once_with(sentinel.t_and_c)
if __name__ == '__main__':
unittest.main()
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