Develop Reference

Why is terminal providing me with zero results for this .py script?

I am learning unittest and am trying to work on the following two .py scripts but when i run on terminal it shows "ran 0 tests". What am i doing wrong?
sanity.py
def firstname(name):
return name.title()
and then the second
sanitycheck.py
import unittest
import sanity
class TestingCap(unittest.TestCase):
def firstone(self):
word = 'apple'
result = sanity.firstname(word)
self.assertEqual(result,'apple')
if __name__ == '__main__':
unittest.main()
Thank you!

By default, unittest assumes that tests in a unittest.TestCase are methods whose names begin with "test_"
Change your test method name to "test_firstone":
import unittest
import sanity
class TestingCap(unittest.TestCase):
def test_firstone(self):
word = 'apple'
result = sanity.firstname(word)
self.assertEqual(result,'apple')
if __name__ == '__main__':
unittest.main()
python sanitycheck.py
F
======================================================================
FAIL: test_firstone (__main__.TestingCap)
----------------------------------------------------------------------
Traceback (most recent call last):
File "sanitycheck.py", line 9, in test_firstone
self.assertEqual(result,'apple')
AssertionError: 'Apple' != 'apple'
- Apple
? ^
+ apple
? ^
----------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (failures=1)
You may change the behavior of unittest if you like. Check out the documentation: https://docs.python.org/3/library/unittest.html

You should name the file with test.
example: test_sanity, sanity_test, testsanity.

Your function names should begin with test then an underscore like:
def test_firstone(self):
...

python unittest mocking / patching

Not wanting to test manually my code, I'm trying to write a test which mocks/patches one of my dependencies (PyInquirer is a pretty neat package which handles the CLI for me - question dicts in, answer dicts out).
However, being very new to Python, I'm having difficulties with mocking that dependency. Here's the code I'm testing:
from PyInquirer import prompt
class Foo:
def bar(self):
# this line is asking the user for inpit, and that's what I want to mock.
a = prompt({'name': 'q',
'type': 'input',
'message': 'well, foo'})
print("f is", f)
return a
And this is the test:
import unittest
from unittest.mock import patch
from Foo import Foo
class TestFoo(unittest.TestCase):
#patch('PyInquirer.prompt', return_value=24)
def test_bar(self):
f = Foo()
a = f.bar()
assert a == 24
if __name__ == '__main__':
unittest.main()
(the real code is obviously more complicated, but this is the essence of the problem). Which manifests itself as:
Error
Traceback (most recent call last):
File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/case.py", line 59, in testPartExecutor
yield
File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/case.py", line 605, in run
testMethod()
File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/mock.py", line 1179, in patched
return func(*args, **keywargs)
TypeError: test_bar() takes 1 positional argument but 2 were given
I'm quite confused.
If I omit the patch decorator, the invocation fails with an expected assertion error - the dictionary produced by prompt isn't equal to 24. But if I do provide the decorator, I get the argument mismatch above. And indeed the last line in the stacktrace does show the function "func", which I presume is what the decorator was applied to, is invoked with two arguments... but... why? Can't be the essence of a problem? That only functions with arity of two can be thus patched =)

Your class uses the name Foo.prompt (because of how you import it), so that's what you need to patch.
class TestFoo(unittest.TestCase):
#patch('Foo.prompt', return_value=24)
def test_bar(self, mock_prompt):
f = Foo()
a = f.bar()
assert a == 24
You also need to add a parameter to test_bar to receive the patched object, whether or not you plan to use it. If you don't want to do that,
you can move the call to patch inside the method, using it with a with statement.
class TestFoo(unittest.TestCase):
def test_bar(self):
with patch('Foo.prompt', return_value=24):
f = Foo()
a = f.bar()
assert a == 24

Chaining Celery Task Methods Error

I'm trying to chain together two task_methods using celery, but I get the following error:
error:
>>> from proj.tasks import A
>>> a = A()
>>> s = (a.add.s(1,2) | a.show.s()).delay().get()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.6/site-packages/celery/result.py", line 175, in get
raise meta['result']
TypeError: show() takes exactly 2 arguments (1 given)
Note, I don't get this error when chaining regular (standalone functions) celery tasks together, only task_methods (class functions). I can't tell if the self object isn't being passed or if the result from the first task isn't being passed.
Here is my project layout:
proj/__init__.py
celery_app.py
tasks.py
tasks.py:
from __future__ import absolute_import
from celery import current_app
from celery.contrib.methods import task_method
from proj.celery_app import app
class A:
def __init__(self):
self.something = 'something'
#current_app.task(filter=task_method)
def add(self,x, y):
return x + y
#current_app.task(filter=task_method)
def show(self,s):
print s
return s
celery_app.py:
from __future__ import absolute_import
from celery import Celery
app = Celery('proj',
broker='amqp://',
backend='amqp://',
include=['proj.tasks'])
app.conf.update(
CELERY_TASK_RESULT_EXPIRES=3600,
)
if __name__ == '__main__':
app.start()
Here's the error from the celery worker:
[2015-04-15 19:57:52,338: ERROR/MainProcess] Task proj.tasks.show[e1e5bc12-6d36-46cd-beb7-fd92a0a5f5c2] raised unexpected: TypeError('show() takes exactly 2 arguments (1 given)',)
Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/celery/app/trace.py", line 240, in trace_task
R = retval = fun(*args, **kwargs)
File "/usr/lib/python2.6/site-packages/celery/app/trace.py", line 438, in __protected_call__
return self.run(*args, **kwargs)
TypeError: show() takes exactly 2 arguments (1 given)
Has anyone successfully chained task_methods with celery? Thanks!
edit: It's also worth noting that the following code is successful:
>>> from proj.tasks import A
>>> a = A()
>>> sum = a.add.s(1,2).delay().get()
>>> show = a.show.s(sum).delay().get()
Also, I know it could be argued that these functions don't need to be in a class, but pretend they do. I used simple functions to help illustrate the question.
EDIT
I've found a workaround, although a better solution is still desired:
First, revise tasks.py:
...
def show(s,self):
print s
return s
...
Then you can call s = (a.add.s(1,1) | a.show.s(a) ).delay().get(), setting s to 2.
Interestingly enough, calling s = (a.add.s(1,1) | a.show.s(self=a) ).delay().get() spits back the following error:
TypeError: s() got multiple values for keyword argument 'self'
This is not ideal, since the show function can not be called unless in a chain.
For example, the following issues:
>>> a.show(s='test')
TypeError: show() got multiple values for keyword argument 's'
and
>>> a.show(s='test',self=a)
TypeError: __call__() got multiple values for keyword argument 'self'

According to Ask Solem Hoel, the creator of Celery, task methods were a "failed experiment", and will no longer be supported. I guess that answers my question - It can't be done, currently.
Source

Nose: generator for TestCase-based classes

I want to create a generator for variations of a TestCase-derived class.
What I tried is this:
import unittest
def create_class(param):
class Test(unittest.TestCase):
def setUp(self):
pass
def test_fail(self):
assert False
return Test
def test_basic():
for i in range(5):
yield create_class(i)
What I get is this:
======================================================================
ERROR: test_1.test_basic
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/lib/python3.3/site-packages/nose/case.py", line 268, in setUp
try_run(self.test, names)
File "/usr/lib/python3.3/site-packages/nose/util.py", line 478, in try_run
return func()
TypeError: setUp() missing 1 required positional argument: 'self'
Yielding instances instead of classes (yield create_class(i)()) leaves me with this error:
======================================================================
ERROR: test_1.test_basic
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/lib/python3.3/site-packages/nose/case.py", line 198, in runTest
self.test(*self.arg)
File "/usr/lib/python3.3/unittest/case.py", line 492, in __call__
return self.run(*args, **kwds)
File "/usr/lib/python3.3/unittest/case.py", line 423, in run
testMethod = getattr(self, self._testMethodName)
AttributeError: 'Test' object has no attribute 'runTest'
Any ideas?

When instantiating a TestCase you should pass the method name of the test:
yield create_class(i)('test_fail')
Otherwise the name defaults to runTest(and thus the last error you got).
Also note that there is a strange interaction between test generators and TestCase. With the following code:
import unittest
def create_class(param):
class Test(unittest.TestCase):
def setUp(self):
pass
def test_fail(self):
print('executed')
assert False
print('after assert')
return Test
def test_basic():
for i in range(5):
yield create_class(i)('test_fail')
I obtain this output:
$ nosetests -s
executed
.executed
.executed
.executed
.executed
.
----------------------------------------------------------------------
Ran 5 tests in 0.004s
OK
As you can see the test does not fail, even though the assert works. This is probably due to the fact that TestCase handles the AssertionError but nose does not expect this to be handled and thus it cannot see that the test failed.
This can be seen from the documentation of TestCase.run:
Run the test, collecting the result into the test result object passed as result. If result is omitted or None, a temporary result
object is created (by calling the defaultTestResult() method) and
used. The result object is not returned to run()‘s caller.
The same effect may be had by simply calling the TestCase instance.
So, nose doesn't see that the objected yielded by the generator is a TestCase which should be handled in a special manner, it simply expects a callable. The TestCase is run, but the result is put into a temporary object that is lost, and this eats all test failures that happen inside the tests. Hence yielding TestCasees simply doesn't work.

I have run the codes you provides. I received no error. The version I use is python2.7. System is ubuntu12.10. Maybe you need to check with python2.7.

Mocking file objects or iterables in python

Which way is proper for mocking and testing code that iters object returned by open(), using mock library?
whitelist_data.py:
WHITELIST_FILE = "testdata.txt"
format_str = lambda s: s.rstrip().lstrip('www.')
whitelist = None
with open(WHITELIST_FILE) as whitelist_data:
whitelist = set(format_str(line) for line in whitelist_data)
if not whitelist:
raise RuntimeError("Can't read data from %s file" % WHITELIST_FILE)
def is_whitelisted(substr):
return 1 if format_str(substr) in whitelist else 0
Here's how I try to test it.
import unittest
import mock
TEST_DATA = """
domain1.com
domain2.com
domain3.com
"""
class TestCheckerFunctions(unittest.TestCase):
def test_is_whitelisted_method(self):
open_mock = mock.MagicMock()
with mock.patch('__builtin__.open',open_mock):
manager = open_mock.return_value.__enter__.return_value
manager.__iter__ = lambda s: iter(TEST_DATA.splitlines())
from whitelist_data import is_whitelisted
self.assertTrue(is_whitelisted('domain1.com'))
if __name__ == '__main__':
unittest.main()
Result of python tests.py is:
$ python tests.py
E
======================================================================
ERROR: test_is_whitelisted_method (__main__.TestCheckerFunctions)
----------------------------------------------------------------------
Traceback (most recent call last):
File "tests.py", line 39, in test_is_whitelisted_method
from whitelist_data import is_whitelisted
File "/Users/supa/Devel/python/whitelist/whitelist_data.py", line 20, in <module>
whitelist = set(format_str(line) for line in whitelist_data)
TypeError: 'Mock' object is not iterable
----------------------------------------------------------------------
Ran 1 test in 0.001s
UPD: Thanks to Adam, I've reinstalled mock library(pip install -e hg+https://code.google.com/p/mock#egg=mock) and updated tests.py. Works like a charm.

You're looking for a MagicMock. This supports iteration.
In mock 0.80beta4, patch returns a MagicMock. So this simple example works:
import mock
def foo():
for line in open('myfile'):
print line
#mock.patch('__builtin__.open')
def test_foo(open_mock):
foo()
assert open_mock.called
If you're running mock 0.7.x (It looks like you are), I don't think you can accomplish this with patch alone. You'll need to create the mock separately, then pass it into patch:
import mock
def foo():
for line in open('myfile'):
print line
def test_foo():
open_mock = mock.MagicMock()
with mock.patch('__builtin__.open', open_mock):
foo()
assert open_mock.called
Note - I've run these with py.test, however, these same approaches will work with unittest as well.