relative import question: packaging scripts

Alan Isaac aisaac at american.edu
Sat Jun 23 10:57:46 EDT 2007


What is the recommended packaging of
demo scripts or test scripts for a package
that has modules that use relative imports?

Example:
Suppose I have the package structure:

package/
    __init__.py
    subpackage1/
        __init__.py
        moduleY.py
    subpackage2/
        __init__.py
        moduleZ.py

Important detail:
moduleZ uses a relative import to access moduleY.

The problem:
I have a script test.py that I want to
distribute with the package.  It will import
moduleZ to illustrate or test the module's use.

Is it the case that this script cannot reasonably be
bundled with `package`?  (I.e., within its directory
structure.)

I cannot put it in the `subpackage2` directory and
just import moduleZ, because then I will get
ValueError: Attempted relative import in non-package

I cannot put it in the `package` directory and
import subpackage2.moduleZ, because then I will get
ValueError: Attempted relative import beyond toplevel package

The script could use path manipulation to
find `package`, as suggested by Alex Martelli
http://mail.python.org/pipermail/python-list/2007-May/438250.html
and others.  However it has also been claimed that this approach is an
insane for any shared code.  Is it?

I do not want to assume the package will be installed:
a user should be able to play with it without installing it.
In this case, does the only "sane" thing to become to
require any user to take the step of inserting the
package location into sys.path and have
test.py rely on the user having done this?

Thank you,
Alan Isaac



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