How do you use factory_boy to model a MongoEngine EmbeddedDocument?

Question

I'm trying to use factory_boy to help generate some MongoEngine documents for my tests. I'm having trouble defining EmbeddedDocumentField objects.

Here's my MongoEngine Document:

class Comment(EmbeddedDocument):
    content = StringField()
    name = StringField(max_length=120)

class Post(Document):
    title = StringField(required=True)
    tags = ListField(StringField(), required=True)
    comments = ListField(EmbeddedDocumentField(Comment))

Here's my partially completed factory_boy Factory:

class CommentFactory(factory.Factory):
    FACTORY_FOR = Comment
    content = "Platinum coins worth a trillion dollars are great"
    name = "John Doe"

class BlogFactory(factory.Factory):
    FACTORY_FOR = Blog
    title = "On Using MongoEngine with factory_boy"
    tags = ['python', 'mongoengine', 'factory-boy', 'django']
    comments = [factory.SubFactory(CommentFactory)] # this doesn't work

Any ideas how to specify the comments field? The problem is that factory-boy attempts to create the Comment EmbeddedDocument.

Bohi

Answer 1

I'm not sure if this is what you want but I just started looking at this problem and this seems to work:

from mongoengine import EmbeddedDocument, Document, StringField, ListField, EmbeddedDocumentField
import factory

class Comment(EmbeddedDocument):
    content = StringField()
    name = StringField(max_length=120)

class Post(Document):
    title = StringField(required=True)
    tags = ListField(StringField(), required=True)
    comments = ListField(EmbeddedDocumentField(Comment))


class CommentFactory(factory.Factory):
    FACTORY_FOR = Comment
    content = "Platinum coins worth a trillion dollars are great"
    name = "John Doe"

class PostFactory(factory.Factory):
    FACTORY_FOR = Post
    title = "On Using MongoEngine with factory_boy"
    tags = ['python', 'mongoengine', 'factory-boy', 'django']
    comments = factory.LazyAttribute(lambda a: [CommentFactory()])

>>> b = PostFactory()
>>> b.comments[0].content
'Platinum coins worth a trillion dollars are great'

I wouldn't be surprised if I'm missing something though.

Bryan

You need to include the EmbeddedDocumentFactory as the first guy has included to create the factory for the embedded document factory when we initialize the main factory. – Occident

Answer 2

The way that I'm doing it right now is to prevent the Factories based on EmbeddedDocuments from building. So, I've setup up an EmbeddedDocumentFactory, like so:

class EmbeddedDocumentFactory(factory.Factory):

    ABSTRACT_FACTORY = True

    @classmethod
    def _prepare(cls, create, **kwargs):                                        
        return super(EmbeddedDocumentFactory, cls)._prepare(False, **kwargs)

Then I inherit from that to create factories for EmbeddedDocuments:

class CommentFactory(EmbeddedDocumentFactory):

    FACTORY_FOR = Comment

    content = "Platinum coins worth a trillion dollars are great"
    name = "John Doe"

This may not be the best solution, so I'll wait on someone else to respond before accepting this as the answer.

Bohi