[TIP] setUp and tearDown behavior

[John Arbash Meinel]

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Michael Foord wrote:
> On 19/01/2010 13:53, Olemis Lang wrote:
>> [snip...]
>>> In case this is expected, is there a way to do it just once for all the
>>> methods?
>>>
>>>      
>> Using standard `unittest` module ? well ... no.
>>
>>    
> Well - you can make setup *effectively* only run the first time using a
> class attribute:
> 
> 
> class SomeTest(unittest.TestCase):
> doneSetup = False
> def setUp(self):
> if not self.__class__.doneSetup:
> self.__class__.doneSetup = True
> self.setUpClass()
> ...

^- just mentioning that using it this way will run setup for each child
class. Which may be what you want, or may not. If you want to run it one
time across all inherited tests, then you need to use:

def setUp(self):
  if not SomeTest.doneSetup:
    ...

At least, that is how I understand setattr(), I could be wrong...

> Making tearDown only run the *last* time is a bit harder (you could hack
> it in with a counter in setUp and only execute tearDown when the counter
> == number of test methods). Builtin support for class level fixtures in
> unittest would be good, even if they are ripe for abuse (shared state
> between fixtures).
> 
> All the best,
> 
> Michael Foord
> 
> 

The problem with a simple counter is that the counter always stays at 0.

setUp() +1 = 1
test1()
tearDown() -1 = 0
setUp() +1 = 1
test2()
tearDown() -1 = 0

etc.

I believe we handle it using "startTestRun()" and "stopTestRun()" but
those are defined for the whole test suite, not for a subset.

A different possibility with the "test_suite()" or "load_tests()"
paradigm, is that you can create a custom TestSuite instance that
overloads run() (I believe) to do something like:

class MySuite(unittest.TestSuite):

 def run(self):
   self.doSuiteSetup()
   unittest.TestSuite.run(self)
   self.doSuiteTearDown()
...

John
=:->
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