I would like to use python unittest setUpClass and tearDownClass methods with arguments. More specifically, here is what I am doing now:
import unittest2 as unittest
cache = VCache(arg1, arg2, arg3)
class Validation(unittest.TestCase):
''' Unit test class with a local cache to avoid intensive network traffic. '''
#classmethod
def setUpClass(cls):
''' Copy all required data locally. '''
super(Validation, cls).setUpClass()
cache.setUp()
#classmethod
def tearDownClass(cls):
''' Remove the cache. '''
super(Validation, cls).tearDownClass()
cache.tearDown()
It works but now I would like to wrap the cache management in a subclass of Validation, to avoid using a global variable and writing the setUpClass and tearDownClass everytime.
This does not work of course because setUpClass() and tearDownClass() do not accept arguments. Any solution?
Related
I am using selenium for end to end testing and I can't get how to use setup_class and teardown_class methods.
I need to set up browser in setup_class method, then perform a bunch of tests defined as class methods and finally quit browser in teardown_class method.
But logically it seems like a bad solution, because in fact my tests will not work with class, but with object. I pass self param inside every test method, so I can access objects' vars:
class TestClass:
def setup_class(cls):
pass
def test_buttons(self, data):
# self.$attribute can be used, but not cls.$attribute?
pass
def test_buttons2(self, data):
# self.$attribute can be used, but not cls.$attribute?
pass
def teardown_class(cls):
pass
And it even seems not to be correct to create browser instance for class.. It should be created for every object separately, right?
So, I need to use __init__ and __del__ methods instead of setup_class and teardown_class?
According to Fixture finalization / executing teardown code, the current best practice for setup and teardown is to use yield instead of return:
import pytest
#pytest.fixture()
def resource():
print("setup")
yield "resource"
print("teardown")
class TestResource:
def test_that_depends_on_resource(self, resource):
print("testing {}".format(resource))
Running it results in
$ py.test --capture=no pytest_yield.py
=== test session starts ===
platform darwin -- Python 2.7.10, pytest-3.0.2, py-1.4.31, pluggy-0.3.1
collected 1 items
pytest_yield.py setup
testing resource
.teardown
=== 1 passed in 0.01 seconds ===
Another way to write teardown code is by accepting a request-context object into your fixture function and calling its request.addfinalizer method with a function that performs the teardown one or multiple times:
import pytest
#pytest.fixture()
def resource(request):
print("setup")
def teardown():
print("teardown")
request.addfinalizer(teardown)
return "resource"
class TestResource:
def test_that_depends_on_resource(self, resource):
print("testing {}".format(resource))
When you write "tests defined as class methods", do you really mean class methods (methods which receive its class as first parameter) or just regular methods (methods which receive an instance as first parameter)?
Since your example uses self for the test methods I'm assuming the latter, so you just need to use setup_method instead:
class Test:
def setup_method(self, test_method):
# configure self.attribute
def teardown_method(self, test_method):
# tear down self.attribute
def test_buttons(self):
# use self.attribute for test
The test method instance is passed to setup_method and teardown_method, but can be ignored if your setup/teardown code doesn't need to know the testing context. More information can be found here.
I also recommend that you familiarize yourself with py.test's fixtures, as they are a more powerful concept.
This might help http://docs.pytest.org/en/latest/xunit_setup.html
In my test suite, I group my test cases into classes. For the setup and teardown I need for all the test cases in that class, I use the setup_class(cls) and teardown_class(cls) classmethods.
And for the setup and teardown I need for each of the test case, I use the setup_method(method) and teardown_method(methods)
Example:
lh = <got log handler from logger module>
class TestClass:
#classmethod
def setup_class(cls):
lh.info("starting class: {} execution".format(cls.__name__))
#classmethod
def teardown_class(cls):
lh.info("starting class: {} execution".format(cls.__name__))
def setup_method(self, method):
lh.info("starting execution of tc: {}".format(method.__name__))
def teardown_method(self, method):
lh.info("starting execution of tc: {}".format(method.__name__))
def test_tc1(self):
<tc_content>
assert
def test_tc2(self):
<tc_content>
assert
Now when I run my tests, when the TestClass execution is starting, it logs the details for when it is beginning execution, when it is ending execution and same for the methods..
You can add up other setup and teardown steps you might have in the respective locations.
Hope it helps!
As #Bruno suggested, using pytest fixtures is another solution that is accessible for both test classes or even just simple test functions. Here's an example testing python2.7 functions:
import pytest
#pytest.fixture(scope='function')
def some_resource(request):
stuff_i_setup = ["I setup"]
def some_teardown():
stuff_i_setup[0] += " ... but now I'm torn down..."
print stuff_i_setup[0]
request.addfinalizer(some_teardown)
return stuff_i_setup[0]
def test_1_that_needs_resource(some_resource):
print some_resource + "... and now I'm testing things..."
So, running test_1... produces:
I setup... and now I'm testing things...
I setup ... but now I'm torn down...
Notice that stuff_i_setup is referenced in the fixture, allowing that object to be setup and torn down for the test it's interacting with. You can imagine this could be useful for a persistent object, such as a hypothetical database or some connection, that must be cleared before each test runs to keep them isolated.
Your code should work just as you expect it to if you add #classmethod decorators.
#classmethod
def setup_class(cls):
"Runs once per class"
#classmethod
def teardown_class(cls):
"Runs at end of class"
See http://pythontesting.net/framework/pytest/pytest-xunit-style-fixtures/
import pytest
class Test:
#pytest.fixture()
def setUp(self):
print("setup")
yield "resource"
print("teardown")
def test_that_depends_on_resource(self, setUp):
print("testing {}".format(setUp))
In order to run:
pytest nam_of_the_module.py -v
I'm not sure I got the specifics of using Selenium in your original questions, but in case you were simply asking about how to use a more classical setUp/tearDown style, Pytest supports most unittest features, so you could do something like:
import unittest
class TestHello(unittest.TestCase):
def setUp(self):
print('running setUp')
def test_one(self):
print('running test_one')
def test_two(self):
print('running test_two')
def tearDown(self):
print('running tearDown')
Which produces:
$ pytest -s -v
====================== test session starts =======================
platform linux -- Python 3.8.2, pytest-6.2.4, py-1.10.0, pluggy-0.13.1 -- /gnu/store/nckjv3ccwdi6096j478gvns43ssbls2p-python-wrapper-3.8.2/bin/python
cachedir: .pytest_cache
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/tmp/test/.hypothesis/examples')
rootdir: /tmp/test
plugins: hypothesis-5.4.1
collected 2 items
test_hw.py::TestHello::test_one running setUp
running test_one
running tearDown
PASSED
test_hw.py::TestHello::test_two running setUp
running test_two
running tearDown
PASSED
I am used to pytest approach for unit testing, without using classes. Today I wanted to give a try to unittest and I wanted to encapsulate my tests inside a TestCase.
Then consider this sample test class:
import unittest
import moto
import boto3
class TestMyClass(unittest.TestCase):
#classmethod
#moto.mock_ssm
def setUpClass(cls) -> None:
cls.ssm_client = boto3.client('ssm')
cls.ssm_client.put_parameter(Name='test', Value='foo', Type='String')
#moto.mock_ssm
def test_something(self):
value = self.ssm_client.get_parameter(Name='test').get('Parameter').get('Value')
self.assertEqual(value, 'foo')
Why is not the parameter placed in setUpClass visible from the test? I could imagine that by using the #moto.mock_ssm decorator there it would all have been done in the mocked context.
I can, however, place the parameter within test_something as just:
#moto.mock_ssm
def test_something(self):
self.ssm_client.put_parameter(Name='test', Value='foo', Type='String')
value = self.ssm_client.get_parameter(Name='test').get('Parameter').get('Value')
self.assertEqual(value, 'foo')
And then it (obviously) works. Why not with my first approach? I do not want to be populating the fake ssm parameter for each test that will rely on it. What is the best way of doing so here?
The reason why I am asking this is because the class I want to test requires this parameter when it is initialised.
The mock-decorators are scoped for that particular function, so data created inside that function will only be available there.
Instead, you can use the class-decorator:
import unittest
import moto
import boto3
#moto.mock_ssm
class TestMyClass(unittest.TestCase):
client = None
def setUp(self) -> None:
self.client = boto3.client('ssm')
self.client.put_parameter(Name='test', Value='foo', Type='String')
def test_something(self):
value = self.client.get_parameter(Name='test').get('Parameter').get('Value')
self.assertEqual(value, 'foo')
Note that I've switched to setUp, instead of setUpClass. Because setUpClass is a classmethod, it is executed before the decorator is applied, and it will try to execute this method against AWS itself.
TL;DR
How can I patch or mock "any functions that are not being called/used directly"?
Sceneario
I have a simple unit-test snippet as
# utils/functions.py
def get_user_agents():
# sends requests to a private network and pulls data
return pulled_data
# my_module/tasks.py
def create_foo():
from utils.functions import get_user_agents
value = get_user_agents()
# do something with value
return some_value
# test.py
class TestFooKlass(unittest.TestCase):
def setUp(self):
create_foo()
def test_foo(self):
...
Here in setUp() method I am calling get_user_agents() function indirectly by calling create_foo(). During this execution I have got socket.timeout exception since get_user_agents() tried to access a private network. So, how can I manipulate the return data or the entire get_user_agents function during the test?
Also, is there any way to persists this mock/patch during the whole test suite execution?
It does not matter that you call the function indirectly - important is to patch it as it is imported. In your example you import the function to be patched locally inside the tested function, so it will only be imported at function run time. In this case you have to patch the function as imported from its module (e.g. 'utils.functions.get_user_agents'):
class TestFooKlass(unittest.TestCase):
def setUp(self):
self.patcher = mock.patch('utils.functions.get_user_agents',
return_value='foo') # whatever it shall return in the test
self.patcher.start() # this returns the patched object, i case you need it
create_foo()
def tearDown(self):
self.patcher.stop()
def test_foo(self):
...
If you had imported the function instead at module level like:
from utils.functions import get_user_agents
def create_foo():
value = get_user_agents()
...
you should have patched the imported instance instead:
self.patcher = mock.patch('my_module.tasks.get_user_agents',
return_value='foo')
As for patching the module for all tests: you can start patching in setUp as shown above, and stop it in tearDown.
I am using selenium for end to end testing and I can't get how to use setup_class and teardown_class methods.
I need to set up browser in setup_class method, then perform a bunch of tests defined as class methods and finally quit browser in teardown_class method.
But logically it seems like a bad solution, because in fact my tests will not work with class, but with object. I pass self param inside every test method, so I can access objects' vars:
class TestClass:
def setup_class(cls):
pass
def test_buttons(self, data):
# self.$attribute can be used, but not cls.$attribute?
pass
def test_buttons2(self, data):
# self.$attribute can be used, but not cls.$attribute?
pass
def teardown_class(cls):
pass
And it even seems not to be correct to create browser instance for class.. It should be created for every object separately, right?
So, I need to use __init__ and __del__ methods instead of setup_class and teardown_class?
According to Fixture finalization / executing teardown code, the current best practice for setup and teardown is to use yield instead of return:
import pytest
#pytest.fixture()
def resource():
print("setup")
yield "resource"
print("teardown")
class TestResource:
def test_that_depends_on_resource(self, resource):
print("testing {}".format(resource))
Running it results in
$ py.test --capture=no pytest_yield.py
=== test session starts ===
platform darwin -- Python 2.7.10, pytest-3.0.2, py-1.4.31, pluggy-0.3.1
collected 1 items
pytest_yield.py setup
testing resource
.teardown
=== 1 passed in 0.01 seconds ===
Another way to write teardown code is by accepting a request-context object into your fixture function and calling its request.addfinalizer method with a function that performs the teardown one or multiple times:
import pytest
#pytest.fixture()
def resource(request):
print("setup")
def teardown():
print("teardown")
request.addfinalizer(teardown)
return "resource"
class TestResource:
def test_that_depends_on_resource(self, resource):
print("testing {}".format(resource))
When you write "tests defined as class methods", do you really mean class methods (methods which receive its class as first parameter) or just regular methods (methods which receive an instance as first parameter)?
Since your example uses self for the test methods I'm assuming the latter, so you just need to use setup_method instead:
class Test:
def setup_method(self, test_method):
# configure self.attribute
def teardown_method(self, test_method):
# tear down self.attribute
def test_buttons(self):
# use self.attribute for test
The test method instance is passed to setup_method and teardown_method, but can be ignored if your setup/teardown code doesn't need to know the testing context. More information can be found here.
I also recommend that you familiarize yourself with py.test's fixtures, as they are a more powerful concept.
This might help http://docs.pytest.org/en/latest/xunit_setup.html
In my test suite, I group my test cases into classes. For the setup and teardown I need for all the test cases in that class, I use the setup_class(cls) and teardown_class(cls) classmethods.
And for the setup and teardown I need for each of the test case, I use the setup_method(method) and teardown_method(methods)
Example:
lh = <got log handler from logger module>
class TestClass:
#classmethod
def setup_class(cls):
lh.info("starting class: {} execution".format(cls.__name__))
#classmethod
def teardown_class(cls):
lh.info("starting class: {} execution".format(cls.__name__))
def setup_method(self, method):
lh.info("starting execution of tc: {}".format(method.__name__))
def teardown_method(self, method):
lh.info("starting execution of tc: {}".format(method.__name__))
def test_tc1(self):
<tc_content>
assert
def test_tc2(self):
<tc_content>
assert
Now when I run my tests, when the TestClass execution is starting, it logs the details for when it is beginning execution, when it is ending execution and same for the methods..
You can add up other setup and teardown steps you might have in the respective locations.
Hope it helps!
As #Bruno suggested, using pytest fixtures is another solution that is accessible for both test classes or even just simple test functions. Here's an example testing python2.7 functions:
import pytest
#pytest.fixture(scope='function')
def some_resource(request):
stuff_i_setup = ["I setup"]
def some_teardown():
stuff_i_setup[0] += " ... but now I'm torn down..."
print stuff_i_setup[0]
request.addfinalizer(some_teardown)
return stuff_i_setup[0]
def test_1_that_needs_resource(some_resource):
print some_resource + "... and now I'm testing things..."
So, running test_1... produces:
I setup... and now I'm testing things...
I setup ... but now I'm torn down...
Notice that stuff_i_setup is referenced in the fixture, allowing that object to be setup and torn down for the test it's interacting with. You can imagine this could be useful for a persistent object, such as a hypothetical database or some connection, that must be cleared before each test runs to keep them isolated.
Your code should work just as you expect it to if you add #classmethod decorators.
#classmethod
def setup_class(cls):
"Runs once per class"
#classmethod
def teardown_class(cls):
"Runs at end of class"
See http://pythontesting.net/framework/pytest/pytest-xunit-style-fixtures/
import pytest
class Test:
#pytest.fixture()
def setUp(self):
print("setup")
yield "resource"
print("teardown")
def test_that_depends_on_resource(self, setUp):
print("testing {}".format(setUp))
In order to run:
pytest nam_of_the_module.py -v
I'm not sure I got the specifics of using Selenium in your original questions, but in case you were simply asking about how to use a more classical setUp/tearDown style, Pytest supports most unittest features, so you could do something like:
import unittest
class TestHello(unittest.TestCase):
def setUp(self):
print('running setUp')
def test_one(self):
print('running test_one')
def test_two(self):
print('running test_two')
def tearDown(self):
print('running tearDown')
Which produces:
$ pytest -s -v
====================== test session starts =======================
platform linux -- Python 3.8.2, pytest-6.2.4, py-1.10.0, pluggy-0.13.1 -- /gnu/store/nckjv3ccwdi6096j478gvns43ssbls2p-python-wrapper-3.8.2/bin/python
cachedir: .pytest_cache
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/tmp/test/.hypothesis/examples')
rootdir: /tmp/test
plugins: hypothesis-5.4.1
collected 2 items
test_hw.py::TestHello::test_one running setUp
running test_one
running tearDown
PASSED
test_hw.py::TestHello::test_two running setUp
running test_two
running tearDown
PASSED
In a hobby project I intend to use nose for testing, I want to put all tests for specific classes into classes since these tests share setup and other functionality. But I can't seem to get nose to execute the setup methods inside the classes.
Here is an example class that is tested:
class mwe():
def __init__(self):
self.example = ""
def setExample(self, ex):
self.example = ex
The tests work, when I don't use classes:
from nose.tools import ok_
import mwe
exampleList = []
def setUp():
print("setup")
exampleList.append("1")
exampleList.append("2")
exampleList.append("3")
def test_Example():
print("test")
for ex in exampleList:
t = mwe.mwe()
t.setExample(ex)
yield check, t, ex
def check(e, ex):
ok_(e.example == ex)
The output is as expected:
setup
test
...
----------------------------------------------------------------------
Ran 3 tests in 0.004s
OK
When a test class is used, the setup method is not executed and therefore no tests are executed.
from nose.tools import ok_
import mwe
class TestexampleClass(object):
def __init__(self):
print("__init__")
self.exampleList = []
def setup(self):
print("setup class")
self.exampleList.append("1")
self.exampleList.append("2")
self.exampleList.append("3")
def test_ExampleClass(self):
print("test class")
for ex in self.exampleList:
t = mwe.mwe()
t.setExample(ex)
yield self.check, t, ex
def check(self, we, ex):
print("check class")
ok_(we.example == ex)
I'm fairly new to python and a newbie with nose, my question is, why is setup not executed? Where is the error in my code?
__init__
test class
----------------------------------------------------------------------
Ran 0 tests in 0.002s
OK
I will be glad for any feedback.
When I use the code from this Question on SO the setup method is executed, as I would expect it.
SOLUTION: After a lot of desperation I found the following:
Nose executes the the class level setup method before the execution of the yielded function, not when the test_* methods are called, as I expected and as is the case for other test_* methods. This obviously goes against the nose documentation:
Setup and teardown functions may be used with test generators. However, please note that setup and teardown attributes attached to the generator function will execute only once. To execute fixtures for each yielded test, attach the setup and teardown attributes to the function that is yielded, or yield a callable object instance with setup and teardown attributes.
Looking at the bug reports, I found the bug report on github.
A possible workaround is to use class level fixtures:
#classmethod
def setup_class(cls):
#do stuff
pass
Your test class needs to extend TestCase and the setup method needs to be called setUp
from unittest import TestCase
class TestUtils(TestCase):
def setUp(self):
self.x = 1
def test_something(self):
self.assertEqual(1, self.x)
which outputs
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK