How Can I Repeat Each Test Multiple Times In A Py.test Run?
Solution 1:
One possible strategy is parameterizing the test in question, but not explicitly using the parameter.
For example:
@pytest.mark.parametrize('execution_number', range(5))defrun_multiple_times(execution_number):
assertTrue
The above test should run five times.
Check out the parametrization documentation: https://pytest.org/latest/parametrize.html
Solution 2:
The pytest module pytest-repeat exists for this purpose, and I recommend using modules where possible, rather than re-implementing their functionality yourself.
To use it simply add pytest-repeat
to your requirements.txt
or pip install pytest-repeat
, then execute your tests with --count n
.
Solution 3:
In order to run each test a number of times, we will programmatically parameterize each test as the tests are being generated.
First, let's add the parser option (include the following in one of your conftest.py's):
defpytest_addoption(parser):
parser.addoption('--repeat', action='store',
help='Number of times to repeat each test')
Now we add a "pytest_generate_tests" hook. Here is where the magic happens.
defpytest_generate_tests(metafunc):
if metafunc.config.option.repeat isnotNone:
count = int(metafunc.config.option.repeat)
# We're going to duplicate these tests by parametrizing them,# which requires that each test has a fixture to accept the parameter.# We can add a new fixture like so:
metafunc.fixturenames.append('tmp_ct')
# Now we parametrize. This is what happens when we do e.g.,# @pytest.mark.parametrize('tmp_ct', range(count))# def test_foo(): pass
metafunc.parametrize('tmp_ct', range(count))
Running without the repeat flag:
(env) $ py.test test.py -vv
============================= test session starts ==============================
platform darwin -- Python 2.7.5 -- py-1.4.20 -- pytest-2.5.2 -- env/bin/python
collected 2 items
test.py:4: test_1 PASSED
test.py:8: test_2 PASSED
=========================== 2 passed in 0.01 seconds ===========================
Running with the repeat flag:
(env) $ py.test test.py -vv --repeat 3
============================= test session starts ==============================
platform darwin -- Python 2.7.5 -- py-1.4.20 -- pytest-2.5.2 -- env/bin/python
collected 6 items
test.py:4: test_1[0] PASSEDtest.py:4: test_1[1] PASSEDtest.py:4: test_1[2] PASSEDtest.py:8: test_2[0] PASSEDtest.py:8: test_2[1] PASSEDtest.py:8: test_2[2] PASSED
=========================== 6 passed in 0.01 seconds ===========================
Further reading:
Solution 4:
Based on Frank T's suggestion, I found a very simple solution in the pytest_generate_tests()
callout:
parser.addoption ('--count', default=1, type='int', metavar='count', help='Run each test the specified number of times')
defpytest_generate_tests (metafunc):
for i inrange (metafunc.config.option.count):
metafunc.addcall()
Now executing py.test --count 5
causes each test to be executed five times in the test session.
And it requires no changes to any of our existing tests.
Solution 5:
Based on what I've seen here, and given that I already do some filtering of tests in pytest_collection_modifyitems
, my method of choice is the following. In conftest.py
defpytest_addoption(parser):
parser.addoption ('--count', default=1, type='int', metavar='count', help='Run each test the specified number of times')
defpytest_collection_modifyitems(session, config, items):
count = config.option.count
items[:] = items * count # add each test multiple times
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