Question

Using py.test, two tests called the same in different directory causes py.test to fail. Why is that? How can I change this without renaming all the tests?

To duplicate do:

; cd /var/tmp/my_test_module
; mkdir -p ook/test           
; mkdir -p eek/test
; touch ook/test/test_proxy.py
; touch eek/test/test_proxy.py
; py.test
============================= test session starts ==============================
platform linux2 -- Python 2.7.3 -- pytest-2.2.4
collected 0 items / 1 errors 

==================================== ERRORS ====================================
___________________ ERROR collecting ook/test/test_proxy.py ____________________
import file mismatch:
imported module 'test_proxy' has this __file__ attribute:
  /home/ygolanski/code/junk/python/mymodule/eek/test/test_proxy.py
which is not the same as the test file we want to collect:
  /home/ygolanski/code/junk/python/mymodule/ook/test/test_proxy.py
HINT: remove __pycache__ / .pyc files and/or use a unique basename for your test file modules
=========================== 1 error in 0.01 seconds ============================

Answer 1

Putting an __init__.py is one way of resolving the conflict. Unlike nose, current pytest does not try to unload test modules in order to import test modules with the same import name. I used to think it’s a bit magic to do this auto-unimporting and might mess up people’s expectation from what the import mechanism does; sometimes people rely on the global state of a test module and with auto-unloading you lose it (a test module importing from another test module might then do unexpected things). But maybe it’s not a practical issue and thus pytest could add a similar hack …