Asserting with..as clause in Python

Question

So, having the unittest.mock and the code

with pysftp.Connection(host, username, password, port) as sftp:
             sftp.get("filename")

... one can assert Connection.assert_called_with(host, username, password, port). But assertion Connection.assert_called_with(host, username, password, port).get("filename") fails.

How do I assert that?

Answer 1

I'm assuming that you would like to patch pysftp.Connection reference.

Here is an example of how you can do your test:

>>> import pysftp
>>> from mock import *

>>> with patch("pysftp.Connection") as mock_connection:
...     with pysftp.Connection("1.2.3.4", "user", "pwd", 12345) as sftp:
...         sftp.get("filename")
...     mock_connection.assert_called_with("1.2.3.4", "user", "pwd", 12345)
...     sftp.get.assert_called_with("filename")
... 
<MagicMock name='Connection().__enter__().get()' id='139907730030992'>

Because sftp object is a MagicMock you can use it directly. As you can see in the log sftp is exactly the same of

mock_connection.return_value.__enter__.return_value

• Connection -> mock_connection
• () -> return_value