Fix binding of db.session to ModelSchema classes

flask_marshmallow/__init__.py

@@ -57,6 +57,8 @@ class Marshmallow(object):
 
     To use it, instantiate with an application::
 
+        from flask import Flask
+
         app = Flask(__name__)
         ma = Marshmallow(app)
 
@@ -112,5 +114,5 @@ def init_app(self, app):
         # If using Flask-SQLAlchemy, attach db.session to ModelSchema
         if has_sqla and 'sqlalchemy' in app.extensions:
             db = app.extensions['sqlalchemy'].db
-            self.ModelSchema.Meta.sqla_session = db.session
+            self.ModelSchema.OPTIONS_CLASS.session = db.session
         app.extensions[EXTENSION_NAME] = self

flask_marshmallow/sqla.py

@@ -15,19 +15,20 @@ class SchemaOpts(msqla.SchemaOpts):
     class Meta. The actual session from `flask_sqlalchemy` gets bound
     in `init_app`.
     """
+    session = DummySession()
 
     def __init__(self, meta):
         if not hasattr(meta, 'sqla_session'):
-            meta.sqla_session = DummySession()
+            meta.sqla_session = self.session
         super(SchemaOpts, self).__init__(meta)
 
 class ModelSchema(msqla.ModelSchema, Schema):
     """ModelSchema that generates fields based on the
     `model` class Meta option, which should be a
     ``db.Model`` class from `flask_sqlalchemy`. Uses the
-    scoped session from `flask_sqlalchemy` by default.
+    scoped session from Flask-SQLAlchemy by default.
 
-    See `<marshmallow_sqlalchemy.ModelSchema>` for more details
+    See `marshmallow_sqlalchemy.ModelSchema` for more details
     on the `ModelSchema` API.
     """
     OPTIONS_CLASS = SchemaOpts

test_flask_marshmallow.py

@@ -246,15 +246,23 @@ def extma(self, extapp):
     @pytest.yield_fixture()
     def models(self, db):
         class AuthorModel(db.Model):
+            __tablename__ = 'author'
             id = db.Column(db.Integer, primary_key=True)
             name = db.Column(db.String(255))
 
+        class BookModel(db.Model):
+            __tablename__ = 'book'
+            id = db.Column(db.Integer, primary_key=True)
+            title = db.Column(db.String(255))
+            author_id = db.Column(db.Integer, db.ForeignKey('author.id'))
+            author = db.relationship('AuthorModel', backref='books')
+
         db.create_all()
 
         class _models:
             def __init__(self):
                 self.Author = AuthorModel
-
+                self.Book = BookModel
         yield _models()
         db.drop_all()