AttributeError thrown by relationship during unit testing

[Sam Raker]

Using SQLAlchemy 1.0.9's declarative extension, I've got a many-to-one relationship defined thusly:

class Article(Base):
   ...
   publisher_id = schema.Column(sqltypes.Integer, schema.ForeignKey('publishers.id'))
...
class Publisher(Base):
   __tablename__ = 'publishers'
   ...
   articles = relationship('Article', backref='publisher')

I've got some code I'd like to test that looks like this:

articles = session.query(Article).filter(...).join(Article.publisher).filter(Publisher.name ==...)...

The code works fine, but while trying to test it with python 2.7's unittest module, I keep getting 

AttributeError: type object 'Article' has no attribute 'publisher'

How do I resolve this? I'm importing both Article and Publisher into my test file. I _really_ don't want to have to connect to a local db just to get instrumented attributes to work properly, and I don't want to have to refactor my code to use Article.publisher_id--as it'd involve either hard-coding (brittle) or two separate ORM/SQL calls (obnoxious)--just to make tests work.

[Michael Bayer]

Sent from my iPhone

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[Michael Bayer]

Two options -  either use back_populates format (search the docs) to set up bidirectional relationships, or call configure_mappers() after the model classes have been defined.

On Jan 11, 2016, at 3:47 PM, Sam Raker <sra...@elitedaily.com> wrote:

[Sam Raker]

I just ended up taking advantage of the fact that you can pass attribute names as strings to join, but thanks for the tips!

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Sam Raker
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