导入Python类（__init__.py问题）

Question

I'm having problems importing Python modules from my project folder into tests folder. Sure I'm missing something, but having read lots of other answers I still can't get it to work.

Folder structure is as follows:

/CorpusBuilder
    /corpusBuilder
        __init__.py
        corpus.py    # contains Corpus class
   /tests
       __init__.py
       test_corpus.py   # trying to import Corpus class — but fails

Exactly what should be the content of each __init__.py file? [Does the top level folder ( CorpusBuilder ) need an __init__.py file as well?] What should the import statement in test_corpus.py say?

Sorry for so many questions: I think I just need a clear example to work from.

Answer 1

There's no need to put anything at all into the __init__.py files. Assuming you're running your tests from the base "CorpusBuilder" directory, or otherwise have put that directory onto the PYTHONPATH, your test_corpus file can simply say from corpusBuilder.corpus import Corpus .

Answer 2

In my approach (according to http://www.scotttorborg.com/python-packaging/index.html ) tests is not at top-level. And no need for an init file there. (assuming the name of your module shall be corpusBuilder). What you will need is a setup.py (again: http://www.scotttorborg.com/python-packaging/minimal.html and https://docs.python.org/2/distutils/setupscript.html ) if you want to run you tests with:

$ python setup.py test

so your structure should be:

CorpusBuilder/
    corpusBuilder/
        corpus.py
        __init__.py
        tests/
           __init__.py
           test_corpus.py
    setup.py
    ...

in corpusBuilder's init you can define imports from submodules. This is useful to not pollute your namespace. For example:

from .submodule import foo

Otherwise, this is just a blank file.

The init file in

tests/

doesn't need anything at all and in your test_corpus you need to import your module. For example:

from unittest import TestCase

import corpusBuilder

class TestOne(TestCase):
    def test_ist_string(self):
        s = minimal.test()
        self.assertTrue(isinstance(s, basestring))

You should be able to run your tests now.