Pick up the docstrings of hybrid properties

Use the docstring of hybrid properties as the description.

Bumped build requirments for sqlalchemy becase as noted in the
documentation before version 1.3.19 the ordering for
all_orm_descriptors was not deterministic:

```
.. versionchanged:: 1.3.19 ensured deterministic ordering for
   :meth:`_orm.Mapper.all_orm_descriptors`.
```

graphene_sqlalchemy/converter.py

@@ -114,6 +114,9 @@ def convert_sqlalchemy_hybrid_method(hybrid_prop, resolver, **field_kwargs):
         # TODO The default type should be dependent on the type of the property propety.
         field_kwargs['type'] = String
 
+    if 'description' not in field_kwargs:
+        field_kwargs['description'] = getattr(hybrid_prop, "__doc__", None)
+
     return Field(
         resolver=resolver,
         **field_kwargs

graphene_sqlalchemy/tests/models.py

@@ -65,6 +65,11 @@ class Reporter(Base):
     articles = relationship("Article", backref="reporter")
     favorite_article = relationship("Article", uselist=False)
 
+    @hybrid_property
+    def hybrid_prop_with_doc(self):
+        """Docstring test"""
+        return self.first_name
+
     @hybrid_property
     def hybrid_prop(self):
         return self.first_name

graphene_sqlalchemy/tests/test_types.py

@@ -82,6 +82,7 @@ class Meta:
         # Composite
         "composite_prop",
         # Hybrid
+        "hybrid_prop_with_doc",
         "hybrid_prop",
         # Relationship
         "pets",
@@ -112,6 +113,12 @@ class Meta:
     # "doc" is ignored by hybrid_property
     assert hybrid_prop.description is None
 
+    # hybrid_prop_with_doc
+    hybrid_prop_with_doc = ReporterType._meta.fields['hybrid_prop_with_doc']
+    assert hybrid_prop_with_doc.type == String
+    # docstring is picked up from hybrid_prop_with_doc
+    assert hybrid_prop_with_doc.description == "Docstring test"
+
     # relationship
     favorite_article_field = ReporterType._meta.fields['favorite_article']
     assert isinstance(favorite_article_field, Dynamic)
@@ -145,6 +152,7 @@ class Meta:
         composite_prop = ORMField()
 
         # hybrid_property
+        hybrid_prop_with_doc = ORMField(description='Overridden')
         hybrid_prop = ORMField(description='Overridden')
 
         # relationships
@@ -172,6 +180,7 @@ class Meta:
         "email_v2",
         "column_prop",
         "composite_prop",
+        "hybrid_prop_with_doc",
         "hybrid_prop",
         "favorite_article",
         "articles",
@@ -207,6 +216,11 @@ class Meta:
     assert hybrid_prop_field.description == "Overridden"
     assert hybrid_prop_field.deprecation_reason is None
 
+    hybrid_prop_with_doc_field = ReporterType._meta.fields['hybrid_prop_with_doc']
+    assert hybrid_prop_with_doc_field.type == String
+    assert hybrid_prop_with_doc_field.description == "Overridden"
+    assert hybrid_prop_with_doc_field.deprecation_reason is None
+
     column_prop_field_v2 = ReporterType._meta.fields['column_prop']
     assert column_prop_field_v2.type == String
     assert column_prop_field_v2.description is None
@@ -275,6 +289,7 @@ class Meta:
         "email",
         "favorite_pet_kind",
         "composite_prop",
+        "hybrid_prop_with_doc",
         "hybrid_prop",
         "pets",
         "articles",
@@ -384,7 +399,7 @@ class Meta:
 
     assert issubclass(CustomReporterType, ObjectType)
     assert CustomReporterType._meta.model == Reporter
-    assert len(CustomReporterType._meta.fields) == 11
+    assert len(CustomReporterType._meta.fields) == 12
 
 
 # Test Custom SQLAlchemyObjectType with Custom Options

setup.py

@@ -15,8 +15,8 @@
     # To keep things simple, we only support newer versions of Graphene
     "graphene>=2.1.3,<3",
     "promise>=2.3",
-    # Tests fail with 1.0.19
-    "SQLAlchemy>=1.2,<2",
+    # Tests fail with 1.3.18
+    "SQLAlchemy>=1.3.19,<2",
     "six>=1.10.0,<2",
     "singledispatch>=3.4.0.3,<4",
 ]

tox.ini

@@ -1,14 +1,12 @@
 [tox]
-envlist = pre-commit,py{27,35,36,37}-sql{11,12,13}
+envlist = pre-commit,py{27,35,36,37}-sql13
 skipsdist = true
 minversion = 3.7.0
 
 [testenv]
 deps =
     .[test]
-    sql11: sqlalchemy>=1.1,<1.2
-    sql12: sqlalchemy>=1.2,<1.3
-    sql13: sqlalchemy>=1.3,<1.4
+    sql13: sqlalchemy>=1.3.19,<1.4
 commands =
     pytest graphene_sqlalchemy --cov=graphene_sqlalchemy {posargs}