Python 如何在 py.test 运行中多次重复每个测试？
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How can I repeat each test multiple times in a py.test run?
提问by Martin Del Vecchio
I want to run each selected py.test item an arbitrary number of times, sequentially.
I don't see any standard py.test mechanism for doing this.
我想按任意次数运行每个选定的 py.test 项目。
我没有看到任何用于执行此操作的标准 py.test 机制。
I attempted to do this in the pytest_collection_modifyitems()hook. I modified the list of items passed in, to specify each item more than once. The first execution of a test item works as expected, but that seems to cause some problems for my code.
我试图在pytest_collection_modifyitems()钩子中做到这一点。我修改了传入的项目列表，以多次指定每个项目。测试项的第一次执行按预期工作，但这似乎给我的代码带来了一些问题。
Further, I would prefer to have a unique test item object for each run, as I use id (item) as a key in various reporting code. Unfortunately, I can't find any py.test code to duplicate a test item, copy.copy()doesn't work, and copy.deepcopy()gets an exception.
此外，我希望每次运行都有一个唯一的测试项对象，因为我在各种报告代码中使用 id (item) 作为键。不幸的是，我找不到任何 py.test 代码来复制测试项，copy.copy()不起作用，并copy.deepcopy()出现异常。
Can anybody suggest a strategy for executing a test multiple times?
有人可以建议多次执行测试的策略吗？
采纳答案by Frank T
In order to run each test a number of times, we will programmatically parameterize each test as the tests are being generated.
为了多次运行每个测试，我们将在生成测试时以编程方式参数化每个测试。
First, let's add the parser option (include the following in one of your conftest.py's):
首先，让我们添加解析器选项（在其中一个 conftest.py 中包含以下内容）：
def pytest_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.
现在我们添加一个“pytest_generate_tests”钩子。这就是魔法发生的地方。
def pytest_generate_tests(metafunc):
if metafunc.config.option.repeat is not None:
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:
在没有重复标志的情况下运行：
(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:
使用重复标志运行：
(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] PASSED
test.py:4: test_1[1] PASSED
test.py:4: test_1[2] PASSED
test.py:8: test_2[0] PASSED
test.py:8: test_2[1] PASSED
test.py:8: test_2[2] PASSED
=========================== 6 passed in 0.01 seconds ===========================
Further reading:
进一步阅读：
回答by Frank T
One possible strategy is parameterizing the test in question, but not explicitly using the parameter.
一种可能的策略是参数化有问题的测试，但不明确使用参数。
For example:
例如：
@pytest.mark.parametrize('execution_number', range(5))
def run_multiple_times(execution_number):
assert True
The above test should run five times.
上面的测试应该运行五次。
Check out the parametrization documentation: https://pytest.org/latest/parametrize.html
回答by Martin Del Vecchio
Based on Frank T's suggestion, I found a very simple solution in the pytest_generate_tests() callout:
根据 Frank T 的建议，我在 pytest_generate_tests() 标注中找到了一个非常简单的解决方案：
parser.addoption ('--count', default=1, type='int', metavar='count', help='Run each test the specified number of times')
def pytest_generate_tests (metafunc):
for i in range (metafunc.config.option.count):
metafunc.addcall()
Now executing "py.test --count 5" causes each test to be executed five times in the test session.
现在执行“py.test --count 5”会导致每个测试在测试会话中执行五次。
And it requires no changes to any of our existing tests.
它不需要对我们现有的任何测试进行更改。
Thanks Frank T!
谢谢弗兰克 T！
回答by jsj
The pytest module pytest-repeatexists for this purpose, and I recommend using modules where possible, rather than re-implementing their functionality yourself.
pytest 模块pytest-repeat为此目的而存在，我建议尽可能使用模块，而不是自己重新实现它们的功能。
To use it simply add pytest-repeatto your requirements.txtor pip install pytest-repeat, then execute your tests with --count n.
要使用它，只需将它添加pytest-repeat到您的requirements.txtor 中pip install pytest-repeat，然后使用--count n.
回答by user7610
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
根据我在这里看到的内容，并且鉴于我已经对 中的测试进行了一些过滤pytest_collection_modifyitems，我选择的方法如下。在conftest.py
def pytest_addoption(parser):
parser.addoption ('--count', default=1, type='int', metavar='count', help='Run each test the specified number of times')
def pytest_collection_modifyitems(session, config, items):
count = config.option.count
items[:] = items * count # add each test multiple times
