Wrong mapfield fields

Hi all,
i'm juggling with strange behaviour passing from 0.8.x to 0.15

In 0.8 this code works perfectly:

from  mongoengine import *

class Component(EmbeddedDocument):
    item = StringField()

class Model(DynamicDocument):
    name = StringField()
    Components = MapField(EmbeddedDocumentField(Component))

d = { 'name': 'root',
        'Components' : {
            'first': {'_cls':'Component', 'item':'foo'},
            'second': {'_cls':'Component', 'item':'bar'}
}}
m = Model(**d)
for c in m.Components.values():
    assert isinstance(c, Component)

But in 0.15 of mongoengine mapfields is populated with dicts, so it fails in the assertion.

This is the main differences:

{'second': <Component: Component object>, 'first': <Component: Component object>}

{'second': {'item': 'bar', '_cls': 'Component'}, 'first': {'item': 'foo', '_cls': 'Component'}}

Is this relathed to DynamicDocument class in any manner?

Thank you
Glauco

Start by running the provided Python reproduction against the affected mongoengine version and compare MapField values with the expected EmbeddedDocument instances. Inspect MapField and EmbeddedDocumentField conversion behavior, then add a regression test covering a DynamicDocument map and verify that its values are Component objects.