Question

I’ve the following source code structure

testapp/
├─ __init__.py
├─ testmsg.py
├─ sub/
│  ├─ __init__.py
│  ├─ testprinter.py

where testmsg defines the following constant:

MSG = "Test message"

and sub/testprinter.py:

import testmsg

print("The message is: {0}".format(testmsg.MSG))

But I’m getting ImportError: No module named testmsg

Shouldn’t it be working since the package structure? I don’t really want to extend sys.path in each submodule and I don’t even want to use relative import.

What am I doing wrong here?

Answer 1

It all depends on which script you run. That script’s path will be added to python’s search path automatically.

Make it the following structure:

TestApp/
├─ testapp/
│  ├─ __init__.py
│  ├─ testmsg.py
│  ├─ sub/
│  │  ├─ __init__.py
│  │  ├─ testprinter.py
├─ README
├─ LICENSE
├─ setup.py
├─ run_test.py

Then run TestApp/run_test.py first:

from testapp.sub.testprinter import functest ; functest()

Then TestApp/testapp/sub/testprinter.py could do:

from testapp.testmsg import MSG
print("The message is: {0}".format(testmsg.MSG))

More good hints here;