A Builder Pattern implementation to create test data objects in Plone

builders.py

from plone.dexterity.utils import createContentInContainer
from plone.namedfile.file import NamedBlobFile
import transaction

def Builder(name):
    if name == "dossier":
        return DossierBuilder(BuilderSession.instance())
    elif name == "document":
        return DocumentBuilder(BuilderSession.instance())
    elif name == "task":
        return TaskBuilder(BuilderSession.instance())
    elif name == "mail":
        return MailBuilder(BuilderSession.instance())
    elif name == "repository":
        return RepositoryBuilder(BuilderSession.instance())
    else:
        raise ValueError("No Builder for %s" % name)


class BuilderSession(object):

    def __init__(self):
        self.reset()

    def reset(self):
        self.portal = None
        self.auto_commit = True

    @classmethod
    def instance(cls, *args, **kwgs):
        if not hasattr(cls, "_instance"):
            cls._instance = cls(*args, **kwgs)
        return cls._instance


class DexterityBuilder(object):

    def __init__(self, session):
        self.session = session
        self.container = session.portal
        self.arguments = {"checkConstraints": False}

    def within(self, container):
        self.container = container
        return self

    def titled(self, title):
        self.arguments["title"] = title
        return self

    def with_description(self, description):
        self.arguments["description"] = description
        return self

    def having(self, **kwargs):
        self.arguments.update(kwargs)
        return self

    def create(self):
        self.before_create()
        obj = self.create_object()
        self.after_create()
        return obj

    def before_create(self):
        pass

    def after_create(self):
        if self.session.auto_commit:
            transaction.commit()


class DossierBuilder(DexterityBuilder):

    def create_object(self):
        return createContentInContainer(self.container,
                                        'opengever.dossier.businesscasedossier',
                                        **self.arguments)


class DocumentBuilder(DexterityBuilder):

    def with_dummy_content(self):
        self.attach_file_containing("Test data")
        return self

    def attach_file_containing(self, content, name=u"test.doc"):
        self.attach(NamedBlobFile(data=content, filename=name))
        return self

    def attach(self, file_):
        self.arguments["file"] = file_
        return self

    def create_object(self):
        return createContentInContainer(self.container,
                                        'opengever.document.document',
                                        **self.arguments)


class TaskBuilder(DexterityBuilder):

    def create_object(self):
        return createContentInContainer(self.container,
                                        'opengever.task.task',
                                        **self.arguments)


class MailBuilder(DexterityBuilder):

    def with_dummy_message(self):
        self.with_message("foobar")
        return self

    def with_message(self, message, filename=u'testmail.eml'):
        file_ = NamedBlobFile(data=message, filename=filename)
        self.arguments["message"] = file_
        return self

    def create_object(self):
        return createContentInContainer(self.container,
                                        'ftw.mail.mail',
                                        **self.arguments)

class RepositoryBuilder(DexterityBuilder):

    def create_object(self):
        return createContentInContainer(self.container,
                                        'opengever.repository.repositoryfolder',
                                        **self.arguments)