69 lines
2.0 KiB
Plaintext
69 lines
2.0 KiB
Plaintext
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pytest_monkeypatch plugin
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=========================
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safely patch object attributes, dicts and environment variables.
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.. contents::
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:local:
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Usage
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----------------
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Use the `monkeypatch funcarg`_ to safely patch environment
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variables, object attributes or dictionaries. For example, if you want
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to set the environment variable ``ENV1`` and patch the
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``os.path.abspath`` function to return a particular value during a test
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function execution you can write it down like this:
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.. sourcecode:: python
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def test_mytest(monkeypatch):
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monkeypatch.setenv('ENV1', 'myval')
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monkeypatch.setattr(os.path, 'abspath', lambda x: '/')
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... # your test code
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The function argument will do the modifications and memorize the
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old state. After the test function finished execution all
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modifications will be reverted. See the `monkeypatch blog post`_
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for an extensive discussion.
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To add to a possibly existing environment parameter you
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can use this example:
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.. sourcecode:: python
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def test_mypath_finding(monkeypatch):
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monkeypatch.setenv('PATH', 'x/y', prepend=":")
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# x/y will be at the beginning of $PATH
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.. _`monkeypatch blog post`: http://tetamap.wordpress.com/2009/03/03/monkeypatching-in-unit-tests-done-right/
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.. _`monkeypatch funcarg`:
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the 'monkeypatch' test function argument
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----------------------------------------
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The returned ``monkeypatch`` funcarg provides three
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helper methods to modify objects, dictionaries or os.environ::
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monkeypatch.setattr(obj, name, value)
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monkeypatch.setitem(mapping, name, value)
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monkeypatch.setenv(name, value)
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All such modifications will be undone when the requesting
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test function finished its execution.
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Start improving this plugin in 30 seconds
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=========================================
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1. Download `pytest_monkeypatch.py`_ plugin source code
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2. put it somewhere as ``pytest_monkeypatch.py`` into your import path
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3. a subsequent ``py.test`` run will use your local version
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Checkout customize_, other plugins_ or `get in contact`_.
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.. include:: links.txt
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