Python Nose Import Error

I can't seem to get the nose testing framework to recognize modules beneath my test script in the file structure. I've set up the simplest example that demonstrates the problem. I'll explain it below.

Here's the the package file structure:

./__init__.py
./foo.py
./tests
   ./__init__.py
   ./test_foo.py

foo.py contains:

def dumb_true():
    return True

tests/test_foo.py contains:

import foo

def test_foo():
    assert foo.dumb_true()

Both init.py files are empty

If I run nosetests -vv in the main directory (where foo.py is), I get:

Failure: ImportError (No module named foo) ... ERROR

======================================================================
ERROR: Failure: ImportError (No module named foo)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python/site-packages/nose-0.11.1-py2.6.egg/nose/loader.py", line 379, in loadTestsFromName
    addr.filename, addr.module)
  File "/usr/lib/python/site-packages/nose-0.11.1-py2.6.egg/nose/importer.py", line 39, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/usr/lib/python/site-packages/nose-0.11.1-py2.6.egg/nose/importer.py", line 86, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/home/user/nose_testing/tests/test_foo.py", line 1, in <module>
    import foo
ImportError: No module named foo

----------------------------------------------------------------------
Ran 1 test in 0.002s

FAILED (errors=1)

I get the same error when I run from inside the tests/ directory. According to the documentation and an example I found, nose is supposed to add all parent packages to the path as well as the directory from which it is called, but this doesn't seem to be happening in my case.

I'm running Ubuntu 8.04 with Python 2.6.2. I've built and installed nose manually (not with setup_tools) if that matters.

Solution 1:

You've got an __init__.py in your top level directory. That makes it a package. If you remove it, your nosetests should work.

If you don't remove it, you'll have to change your import to import dir.foo, where dir is the name of your directory.

Solution 2:

Are you in a virtualenv? In my case, nosetests was the one in /usr/bin/nosetests, which was using /usr/bin/python. The packages in the virtualenv definitely won't be in the system path. The following fixed this:

source myvirtualenv/activate
pip install nose
which nosetests
/home/me/myvirtualenv/bin/nosetests

Solution 3:

To those of you finding this question later on: I get the import error if I don't have an __init__.py file in my tests directory.

My directory structure was like this:

./tests/
  ./test_some_random_stuff.py

If I ran nosetests:

nosetests -w tests

It would give the ImportError that everyone else is seeing. If I add a blank __init__.py file it works just fine:

./tests/
  ./__init__.py
  ./test_some_random_stuff.py

Solution 4:

Another potential problem appears to be hyphens/dashes in the directory tree. I recently fixed a nose ImportError issue by renaming a directory from sub-dir to sub_dir.