[testlib] Fix datadir property (closes #294478)

Quoting `pydoc __import__`: "When importing a module from a package,
note that __import__('A.B', ...) returns package A".
`importlib.import_module` will always return module A.B in this respect.

The underlying problem is that, when running test using something else
than pytest this `__import__` call will generate wrong results. For
instance, considering from CubicWeb tests, running:

    python -m unittest cubicweb.test.unittest_cwconfig.CubicWebConfigurationTC.test_appobjects_path

__import__('cubicweb.test.unittest_cwconfig') will return the 'cubicweb'
module, not 'cubicweb.test.unittest_cwconfig'.

Since the module is imported (`cls` is a subclass coming from it), we
can just look it up in sys.modules.

This is part of an attempt to use something else than pytest to run
tests in CubicWeb.

1 files changed, 1 insertions, 1 deletions

diff --git a/logilab/common/testlib.py b/logilab/common/testlib.py
index 6f576e9..bb84aaa 100644
--- a/logilab/common/testlib.py
+++ b/logilab/common/testlib.py
@@ -484,7 +484,7 @@ class TestCase(unittest.TestCase):
 
         NOTE: this is a logilab's standard
         """
-        mod = __import__(cls.__module__)
+        mod = sys.modules[cls.__module__]
         return osp.join(osp.dirname(osp.abspath(mod.__file__)), 'data')
     # cache it (use a class method to cache on class since TestCase is
     # instantiated for each test run)