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Replacement for unittest.mock.mock_open #69876
Description
| BPO | 25690 |
|---|---|
| Nosy | @rbtcollins, @ezio-melotti, @bitdancer, @voidspace |
| Files |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = None
created_at = <Date 2015-11-21.16:23:03.721>
labels = ['tests', 'type-feature', 'library']
title = 'Replacement for unittest.mock.mock_open'
updated_at = <Date 2016-03-15.19:54:14.977>
user = 'https://bugs.python.org/NivBen-David'bugs.python.org fields:
activity = <Date 2016-03-15.19:54:14.977>
actor = 'Niv Ben-David'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)', 'Tests']
creation = <Date 2015-11-21.16:23:03.721>
creator = 'Niv Ben-David'
dependencies = []
files = ['41113', '41762', '42175']
hgrepos = []
issue_num = 25690
keywords = ['patch']
message_count = 5.0
messages = ['255061', '255078', '259268', '261714', '261825']
nosy_count = 5.0
nosy_names = ['rbcollins', 'ezio.melotti', 'r.david.murray', 'michael.foord', 'Niv Ben-David']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue25690'
versions = ['Python 3.6']
Activity
NivBen-David commentedon Nov 21, 2015
The unittest.mock module defines a mock_open utility to mock the builtin open function.
During a recent project I found I needed something more. Specifically, mocking different files at the same time, better mocking for operations (like seek, readlines, etc.) among others.
The project can also be found on http://github.com/nivbend/mock-open
Thanks
bitdancer commentedon Nov 22, 2015
Thanks for the submission. I haven't looked at this in detail, but the fact that you are changing existing unit tests indicates there is probably a backward compatibility problem with your patch. Also if you are adding features I'd expect there to be doc changes, which would make it easier to understand what you are proposing.
NivBen-David commentedon Jan 30, 2016
Regarding the documentation changes, my version simply mocks
openmore "closely", so for the most part I can't think of any changes to the documentation. I've added a bit about the mock object acting as a map of file names to mock objects. Should I add anything else?Regarding the tests, I've tried changing as little as possible to make sure I don't have any backward compatibility issues. However, some changes had to be made:
open's mode is 'r', the new mock_open imitates this behavior, and so the test shows. Also, callingopenas a context manager will callclosein__exit__. These are the majority of changes to the testing code.createargument topatch. Must've been by accident. Fixed this in the new patch.Sorry about the (very) late response, I've been preoccupied lately.
rbtcollins commentedon Mar 14, 2016
Hmm, I haven't looked closely, but some high level thoughts.
I'm worried about making mock too complex here. We already say folk should use a VFS for complex file based tests, and there's quite a chunk of code you're adding - perhaps better to just use a VFS?
I don't like mock importing mock_open and mock_open importing mock: please keep this in a single mock.py at this point.
NivBen-David commentedon Mar 15, 2016
I copied the code in place of the old mock_open in unittest/mock.py.
Regarding the VFS issue, I think that it really depends on what you're trying to test. If you only care about "side effects" on the file system, the VFS way it much better and easier. But if you want to test the way files are handled by your code (proper handling of errors during open/read/write seems the obvious thing here, but I can think of other use cases), then I think MockOpen is the better tool.