More tests for attr observers

sqlalchemy_utils/decorators.py

@@ -90,12 +90,13 @@ class AttributeValueGenerator(object):
                 )
             elif index == len(path) - 1:
                 inversed_path = ~path[0:-1]
-                entities = list(
+                entities = getdotattr(
-                    getdotattr(
                     target,
                     str(inversed_path)
                 )
-                )
+                if entities:
+                    if not isinstance(entities, list):
+                        entities = [entities]
                     for entity in entities:
                         if isinstance(entity, list):
                             for e in entity:
@@ -112,12 +113,13 @@ class AttributeValueGenerator(object):
                             )
             else:
                 inversed_path = ~path[0:-1]
-                entities = list(
+                entities = getdotattr(
-                    getdotattr(
                     target,
                     str(inversed_path[index:])
                 )
-                )
+                if entities:
+                    if not isinstance(entities, list):
+                        entities = [entities]
                     for entity in entities:
                         setattr(
                             entity,

sqlalchemy_utils/functions/orm.py

@@ -251,6 +251,8 @@ def getdotattr(obj_or_class, dot_path):
             last = tmp
         elif isinstance(last, InstrumentedAttribute):
             last = getter(last.property.mapper.class_)
+        elif last is None:
+            return None
         else:
             last = getter(last)
     return last

sqlalchemy_utils/path.py

@@ -85,6 +85,9 @@ class AttrPath(object):
                         prop.parent.class_.__name__
                     )
                 )
+            if isinstance(backref, tuple):
+                return backref[0]
+            else:
                 return backref
 
         if isinstance(self.parts[-1].property, sa.orm.ColumnProperty):

tests/test_generates.py

@@ -170,9 +170,86 @@ class TestInstantAttributeValueGeneration(TestCase):
         document = self.Document(name=u'Document 1', locale='en')
         section = self.Section(name=u'Section 1', document=document)
         subsection = self.SubSection(name=u'Section 1', section=section)
-        assert subsection.locale == 'en'
         document.locale = 'fi'
         assert subsection.locale == 'fi'
+
+    def test_simple_assignment(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        assert subsection.locale == 'en'
+
+    def test_intermediate_object_reference(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
         section.document = self.Document(name=u'Document 2', locale='sv')
         assert subsection.locale == 'sv'
 
+
+class TestInstantAttrGenerationWithScalars(TestCase):
+    def create_models(self):
+        class Document(self.Base):
+            __tablename__ = 'document'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+        class Section(self.Base):
+            __tablename__ = 'section'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+            document_id = sa.Column(
+                sa.Integer, sa.ForeignKey(Document.id)
+            )
+
+            document = sa.orm.relationship(
+                Document,
+                backref=sa.orm.backref('section', uselist=False)
+            )
+
+        class SubSection(self.Base):
+            __tablename__ = 'subsection'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column(sa.Unicode(255))
+            locale = sa.Column(sa.String(10))
+
+            section_id = sa.Column(
+                sa.Integer, sa.ForeignKey(Section.id)
+            )
+
+            section = sa.orm.relationship(
+                Section,
+                backref=sa.orm.backref('subsection', uselist=False)
+            )
+
+            @generates(locale, source='section.document.locale')
+            def copy_locale(self, value):
+                return value
+
+
+        self.Document = Document
+        self.Section = Section
+        self.SubSection = SubSection
+
+    def test_change_parent_attribute(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        document.locale = 'fi'
+        assert subsection.locale == 'fi'
+
+    def test_simple_assignment(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        assert subsection.locale == 'en'
+
+    def test_intermediate_object_reference(self):
+        document = self.Document(name=u'Document 1', locale='en')
+        section = self.Section(name=u'Section 1', document=document)
+        subsection = self.SubSection(name=u'Section 1', section=section)
+        section.document = self.Document(name=u'Document 2', locale='sv')
+        assert subsection.locale == 'sv'