Question about packages

[djw]

I'm sturcturing my (relatively) large application into packages and am
having trouble understanding one aspect of module/package paths.

If I have a structure like:

in /:
appA.py
__init__.py

in X/:
modX1.py
modX2.py
__init__.py

in Y:/
modY1.py
__init__.py

Now, if I do the following imports and run appA.py, all is well:

in appA.py:
from X import modX1
import Y.modY1

in modX1:
import modX2

in modY1: (as long as run from appA.py)
import X.modX1

But, if I try to create a test harness inside modY1 (in an if statement
checking __name__ with "__main__") and run modY1.py with the last import
(import X.modX1), I get an ImportError.

So, the question is, how do you import into a sub-package to allow both
a script at the root level to import the module ("library mode") and for
the module itself to run in "test harness" mode with the same import?

Any hints appreciated.

-Don

 

[Mark McEahern]

So, the question is, how do you import into a sub-package to allow both
a script at the root level to import the module ("library mode") and for
the module itself to run in "test harness" mode with the same import?

You could do something like:

try:
import X.modX1
except ImportError:
if __name__ == '__main__':
# Hmm, must be running the test harness, adjust
# sys.path appropriately, then retry import
import sys
sys.path.insert(0, whatever)
import X.modX1

but that smells.

Maybe it's best to separate tests from code?

Cheers,

// m