1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
flaky
=====
.. image:: http://opensource.box.com/badges/stable.svg
:target: http://opensource.box.com/badges
.. image:: https://github.com/box/flaky/actions/workflows/tox.yml/badge.svg?branch=master&event=push
:target: https://github.com/box/flaky/actions/workflows/tox.yml
.. image:: https://img.shields.io/pypi/v/flaky.svg
:target: https://pypi.python.org/pypi/flaky
About
-----
Flaky is a plugin for pytest that automatically reruns flaky tests.
Ideally, tests reliably pass or fail, but sometimes test fixtures must rely on components that aren't 100%
reliable. With flaky, instead of removing those tests or marking them to @skip, they can be automatically
retried.
For more information about flaky, see `this presentation <http://opensource.box.com/flaky/>`_.
Marking tests flaky
~~~~~~~~~~~~~~~~~~~
To mark a test as flaky, simply import flaky and decorate the test with @flaky:
.. code-block:: python
from flaky import flaky
.. code-block:: python
@flaky
def test_something_that_usually_passes(self):
value_to_double = 21
result = get_result_from_flaky_doubler(value_to_double)
self.assertEqual(result, value_to_double * 2, 'Result doubled incorrectly.')
By default, flaky will retry a failing test once, but that behavior can be overridden by passing values to the
flaky decorator. It accepts two parameters: max_runs, and min_passes; flaky will run tests up to max_runs times, until
it has succeeded min_passes times. Once a test passes min_passes times, it's considered a success; once it has been
run max_runs times without passing min_passes times, it's considered a failure.
.. code-block:: python
@flaky(max_runs=3, min_passes=2)
def test_something_that_usually_passes(self):
"""This test must pass twice, and it can be run up to three times."""
value_to_double = 21
result = get_result_from_flaky_doubler(value_to_double)
self.assertEqual(result, value_to_double * 2, 'Result doubled incorrectly.')
Marking a class flaky
+++++++++++++++++++++
In addition to marking a single test flaky, entire test cases can be marked flaky:
.. code-block:: python
@flaky
class TestMultipliers(TestCase):
def test_flaky_doubler(self):
value_to_double = 21
result = get_result_from_flaky_doubler(value_to_double)
self.assertEqual(result, value_to_double * 2, 'Result doubled incorrectly.')
@flaky(max_runs=3)
def test_flaky_tripler(self):
value_to_triple = 14
result = get_result_from_flaky_tripler(value_to_triple)
self.assertEqual(result, value_to_triple * 3, 'Result tripled incorrectly.')
The @flaky class decorator will mark test_flaky_doubler as flaky, but it won't override the 3 max_runs
for test_flaky_tripler (from the decorator on that test method).
Pytest marker
+++++++++++++
When using ``pytest``, ``@pytest.mark.flaky`` can be used in place of ``@flaky``.
Don't rerun certain types of failures
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Depending on your tests, some failures are obviously not due to flakiness. Instead of rerunning
after those failures, you can specify a filter function that can tell flaky to fail the test right away.
.. code-block:: python
def is_not_crash(err, *args):
return not issubclass(err[0], ProductCrashedError)
@flaky
def test_something():
raise ProductCrashedError
@flaky(rerun_filter=is_not_crash)
def test_something_else():
raise ProductCrashedError
Flaky will run ``test_something`` twice, but will only run ``test_something_else`` once.
It can also be used to incur a delay between test retries:
.. code-block:: python
import time
def delay_rerun(*args):
time.sleep(1)
return True
@flaky(rerun_filter=delay_rerun)
def test_something_else():
...
Activating the plugin
~~~~~~~~~~~~~~~~~~~~~
With pytest, flaky will automatically run. It can, however be disabled via the command line:
.. code-block:: console
pytest -p no:flaky
Command line arguments
~~~~~~~~~~~~~~~~~~~~~~
No Flaky Report
+++++++++++++++
Pass ``--no-flaky-report`` to suppress the report at the end of the run detailing flaky test results.
Shorter Flaky Report
++++++++++++++++++++
Pass ``--no-success-flaky-report`` to suppress information about successful flaky tests.
Force Flaky
+++++++++++
Pass ``--force-flaky`` to treat all tests as flaky.
Pass ``--max-runs=MAX_RUNS`` and/or ``--min-passes=MIN_PASSES`` to control the behavior of flaky if ``--force-flaky``
is specified. Flaky decorators on individual tests will override these defaults.
*Additional usage examples are in the code - see test/test_pytest/test_pytest_example.py*
Installation
------------
To install, simply:
.. code-block:: console
pip install flaky
Compatibility
-------------
Flaky is tested with the following test runners and options:
- Py.test. Works with ``pytest-xdist`` but not with the ``--boxed`` option. Doctests cannot be marked flaky.
Contributing
------------
See `CONTRIBUTING.rst <https://github.com/box/flaky/blob/master/CONTRIBUTING.rst>`_.
Setup
~~~~~
Create a virtual environment and install packages -
.. code-block:: console
mkvirtualenv flaky
pip install -r requirements-dev.txt
Testing
~~~~~~~
Run all tests using -
.. code-block:: console
tox
The tox tests include code style checks via pycodestyle and pylint.
Copyright and License
---------------------
::
Copyright 2015 Box, Inc. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
|
