I have a large set of scenarios defined as pytest fixtures. I would like to run my test suite with all these scenarios. The following example gives a quite satisfying solution :
import pytest
# ----------------------------------------
# My scenarios
#pytest.fixture()
def scn_1():
return 1
#pytest.fixture()
def scn_2():
return 2
#pytest.fixture()
def scn_3():
return 3
# -------------------------------------------------
# A fixture collecting all the scenarios
#pytest.fixture(params=['scn_1', 'scn_2', 'scn_3'])
def scn_result(request):
scn_name = request.param
return request.getfixturevalue(scn_name)
# ----------------------------------------------
# my test suite
def test_a(scn_result):
assert scn_result in [1,2,3]
def test_b(scn_result):
assert scn_result in [1,2,3,4]
The problem is that I have to list manually all the fixture names. Is there a way to parametrize the fixture scn_result with all the fixture whose name starts with "scn_" ? Or any solution allowing to parametrize automatically the tests with all these fixtures.
Related
I want to collect information from all my tests, to ensure that I've covered everything, but none of the posts I've come across seem to do this specifically.
If I use e.g. atexit, sessionfinish or other means mentioned when searching for "pytest function after all tests", I seem to lose the ability to use the fixture, and they seem like they're just teardown functions, rather than actual tests.
I want to be able to assert that 1 and 2 are in my fixture list, after running all tests.
import pytest
#pytest.fixture(scope="module")
def fxtr_test_list():
return []
def test_something_1(fxtr_test_list):
fxtr_test_list.append(1)
def test_something_2(fxtr_test_list):
fxtr_test_list.append(2)
#pytest.fixture(scope="session")
def global_check(request, fxtr_test_list):
assert len(fxtr_test_list) == 0 # initial check, should pass
def final_check(request):
assert len(fxtr_test_list) == 0 # final check, should fail
request.addfinalizer(final_check)
return request
You can use fixtures only in tests or other fixtures, so using a fixture in some hook is not possible.
If you don't need a dedicated test, you could just use the fixture itself for testing by making it an autouse-fixture:
import pytest
#pytest.fixture(scope="session")
def fxtr_test_list():
return []
...
#pytest.fixture(scope="session", autouse=True)
def global_check(request, fxtr_test_list):
assert len(fxtr_test_list) == 0 # initial check, should pass
yield
assert len(fxtr_test_list) == 0 # final check, should fail
Note that I changed the scope of the first fixture to "session", otherwise it cannot be used with sesssion-based fixture. Also, I have simplified the second fixture to use the standard setup / yield/ teardown pattern.
This gives you something like:
$ python -m pytest -v test_after_all.py
=================================================
...
collected 2 items
test_after_all.py::test_something_1 PASSED
test_after_all.py::test_something_2 PASSED
test_after_all.py::test_something_2 ERROR
======================================================= ERRORS ========================================================
________________________________________ ERROR at teardown of test_something_2 ________________________________________
request = <SubRequest 'global_check' for <Function test_something_1>>, fxtr_test_list = [1, 2]
#pytest.fixture(scope="session", autouse=True)
def global_check(request, fxtr_test_list):
assert len(fxtr_test_list) == 0 # initial check, should pass
yield
> assert len(fxtr_test_list) == 0 # final check, should fail
E assert 2 == 0
E +2
E -0
...
============================================= 2 passed, 1 error in 0.23s ==============================================
If you really need a dedicated test as the last test, could could use an ordering plugin like pytest-order and mark the test as the last:
#pytest.mark.order(-1)
def test_all_tests(global_check):
...
I would like to use a flexible fixture for a data call that can be reused across the test suite. For this purpose I like to ideally pass on more than on parameter. However the code fragment below generally works only for one parameter:
#pytest.fixture
def getData(request):
"""Variable data query"""
data_detail = request.param
In the pytest documentation there is no hint that more than one parameter may work, e.g. such as:
#pytest.fixture
def getData(request):
"""Variable data query"""
data_detail = request.param[0]
time_detail = request.param[1]
Does anyone have a hint how to build a pytest fixture to which several parameters / arguments may be passed on?
You can use a tuple or a dict as the fixture parameter:
#pytest.fixture
def tuple_params(request):
yield sum(request.param)
#pytest.mark.parametrize("tuple_params", [(1, 2, 3)], indirect=True)
def test_tuple_params(tuple_params):
print(tuple_params) # 6
#pytest.fixture
def dict_params(request):
yield f"{request.param['a']}_{request.param['b']}"
#pytest.mark.parametrize("dict_params", [{"a": "foo", "b": "bar"}],
indirect=True)
def test_dict_params(dict_params):
print(dict_params) # foo_bar
Generally, the parameter can be any object, so you can always put your fixture parameters in a suitable object.
With a tuple or a list parameter, you can also access the values per index as in your example.
I use testinfra with ansible transport. It provides host fixture which has ansible, so I can do host.ansible.get_variables().
Now I need to create a parametrization of test based on value from this inventory.
Inventory:
foo:
hosts:
foo1:
somedata:
- data1
- data2
I want to write a test which tests each of 'data' from somedata for each host in inventory. 'Each host' part is handled by testnfra, but I'm struggling with parametrization of the test:
#pytest.fixture
def somedata(host):
return host.ansible.get_variables()["somedata"]
#pytest.fixture(params=somedata):
def data(request):
return request.param
def test_data(host, data):
assert 'data' in data
I've tried both ways:
#pytest.fixture(params=somedata) -> TypeError: 'function' object is not iterable
#pytest.fixture(params=somedata()) -> Fixture "somedata" called directly. Fixtures are not meant to be called directly...
How can I do this? I understand that I can't change the number of tests at test time, but I pretty sure I have the same inventory at collection time, so, theoretically, it can be doable...
After reading a lot of source code I have came to conclusion, that it's impossible to call fixtures at collection time. There are no fixtures at collection time, and any parametrization should happen before any tests are called. Moreover, it's impossible to change number of tests at test time (so no fixture could change that).
Answering my own question on using Ansible inventory to parametrize a test function: It's possible, but it requires manually reading inventory, hosts, etc. There is a special hook for that: pytest_generate_tests (it's a function, not a fixture).
My current code to get any test parametrized by host_interface fixture is:
def cartesian(hosts, ar):
for host in hosts:
for interface in ar.get_variables(host).get("interfaces",[]):
yield (host, interface)
def pytest_generate_tests(metafunc):
if 'host_interface' in metafunc.fixturenames:
inventory_file = metafunc.config.getoption('ansible_inventory')
ansible_config = testinfra.utils.ansible_runner.get_ansible_config()
inventory = testinfra.utils.ansible_runner.get_ansible_inventory(ansible_config, inventory_file)
ar = testinfra.utils.ansible_runner.AnsibleRunner(inventory_file)
hosts = ar.get_hosts(metafunc.config.option.hosts)
metafunc.parametrize("host_interface", cartesian(hosts, ar))
You should use helper function instead of fixture to parametrize another fixture. Fixtures can not be used as decorator parameters in pytest.
def somedata(host):
return host.ansible.get_variables()["somedata"]
#pytest.fixture(params=somedata()):
def data(request):
return request.param
def test_data(host, data):
assert 'data' in data
This assumes that the host is not a fixture.
If the host is a fixture, there is hacky way to get around the problem. You should write the parameters to a tmp file or in a environment variable and read it with a helper function.
import os
#pytest.fixture(autouse=True)
def somedata(host):
os.environ["host_param"] = host.ansible.get_variables()["somedata"]
def get_params():
return os.environ["host_param"] # do some clean up to return a list instead of a string
#pytest.fixture(params=get_params()):
def data(request):
return request.param
def test_data(host, data):
assert 'data' in data
In my test suite, I have certain data-generation fixtures which are used with many parameterized tests. Some of these tests would want these fixtures to run only once per session, while others need them to run every function. For example, I may have a fixture similar to:
#pytest.fixture
def get_random_person():
return random.choice(list_of_people)
and 2 parameterized tests, one which wants to use the same person for each test condition and one which wants a new person each time. Is there any way for this fixture to have scope="session" for one test and scope="function" for another?
James' answer is okay, but it doesn't help if you yield from your fixture code. This is a better way to do it:
# Built In
from contextlib import contextmanager
# 3rd Party
import pytest
#pytest.fixture(session='session')
def fixture_session_fruit():
"""Showing how fixtures can still be passed to the different scopes.
If it is `session` scoped then it can be used by all the different scopes;
otherwise, it must be the same scope or higher than the one it is used on.
If this was `module` scoped then this fixture could NOT be used on `fixture_session_scope`.
"""
return "apple"
#contextmanager
def _context_for_fixture(val_to_yield_after_setup):
# Rather long and complicated fixture implementation here
print('SETUP: Running before the test')
yield val_to_yield_after_setup # Let the test code run
print('TEARDOWN: Running after the test')
#pytest.fixture(session='function')
def fixture_function_scope(fixture_session_fruit):
with _context_for_fixture(fixture_session_fruit) as result:
yield result
#pytest.fixture(scope='class')
def fixture_class_scope(fixture_session_fruit):
with _context_for_fixture(fixture_session_fruit) as result:
yield result
#pytest.fixture(scope='module')
def fixture_module_scope(fixture_session_fruit):
with _context_for_fixture(fixture_session_fruit) as result:
yield result
#pytest.fixture(scope='session')
def fixture_session_scope(fixture_session_fruit):
with _context_for_fixture(fixture_session_fruit) as result:
# NOTE if the `_context_for_fixture` just did `yield` without any value,
# there should still be a `yield` here to keep the fixture
# inside the context till it is done. Just remove the ` result` part.
yield result
This way you can still handle contextual fixtures.
Github issue for reference: https://github.com/pytest-dev/pytest/issues/3425
One way to do this to separate out the implementation and then have 2 differently-scoped fixtures return it. So something like:
def _random_person():
return random.choice(list_of_people)
#pytest.fixture(scope='function')
def get_random_person_function_scope():
return _random_person()
#pytest.fixture(scope='session')
def get_random_person_session_scope():
return _random_person()
I've been doing this:
def _some_fixture(a_dependency_fixture):
def __some_fixture(x):
return x
yield __some_fixture
some_temp_fixture = pytest.fixture(_some_fixture, scope="function")
some_module_fixture = pytest.fixture(_some_fixture, scope="module")
some_session_fixture = pytest.fixture(_some_fixture, scope="session")
Less verbose than using a context manager.
Actually there is a workaround for this using the request object.
You could do something like:
#pytest.fixture(scope='class')
def get_random_person(request):
request.scope = getattr(request.cls, 'scope', request.scope)
return random.choice(list_of_people)
Then back at the test class:
#pytest.mark.usefixtures('get_random_person')
class TestSomething:
scope = 'function'
def a_random_test():
def another_test():
However, this only works properly for choosing between 'function' and 'class' scope and particularly if the fixture starts as class-scoped (and then changes to 'function' or is left as is).
If I try the other way around (from 'function' to 'class') funny stuff happen and I still can't figure out why.
I have a use case where I may use fixture multiple times inside a test in a "context manager" way. See example code below:
in conftest.py
class SomeYield(object):
def __enter__(self):
log.info("SomeYield.__enter__")
def __exit__(self, exc_type, exc_val, exc_tb):
log.info("SomeYield.__exit__")
def generate_name():
name = "{current_time}-{uuid}".format(
current_time=datetime.now().strftime("%Y-%m-%d-%H-%M-%S"),
uuid=str(uuid.uuid4())[:4]
)
return name
#pytest.yield_fixture
def some_yield():
name = generate_name()
log.info("Start: {}".format(name))
yield SomeYield()
log.info("End: {}".format(name))
in test_some_yield.py
def test_some_yield(some_yield):
with some_yield:
pass
with some_yield:
pass
Console output:
INFO:conftest:Start: 2017-12-06-01-50-32-5213
INFO:conftest:SomeYield.__enter__
INFO:conftest:SomeYield.__exit__
INFO:conftest:SomeYield.__enter__
INFO:conftest:SomeYield.__exit__
INFO:conftest:End: 2017-12-06-01-50-32-5213
Questions:
If I have some setup code in SomeYield.enter and cleanup code in
SomeYield.exit, is this the right way to do it using fixture for
multiple calls in my test?
Why didn't I see three occurrences of
enter and exit? Is this expected?