Change: Improve Model class for invalid data while parsing child mode…

…ls (#904)

Handle the situation more carefully when child models should be parsed
but the response doesn't contain an object/dict.

pontos/models/__init__.py

@@ -150,6 +150,12 @@ def from_dict(cls, data: Dict[str, Any]):
                     "updated_at": "2017-07-08T16:18:44-04:00",
                 })
         """
+        if not isinstance(data, dict):
+            raise ValueError(
+                f"Invalid data for creating an instance of {cls.__name__} "
+                f"model. Data is {data!r}"
+            )
+
         kwargs = {}
         additional_attrs = {}
         type_hints = get_type_hints(cls)
@@ -161,7 +167,7 @@ def from_dict(cls, data: Dict[str, Any]):
                 elif value is not None:
                     model_field_cls = type_hints.get(name)
                     value = cls._get_value(model_field_cls, value)  # type: ignore # pylint: disable=line-too-long # noqa: E501
-            except TypeError as e:
+            except (ValueError, TypeError) as e:
                 raise ModelError(
                     f"Error while creating {cls.__name__} model. Could not set "
                     f"value for property '{name}' from '{value}'."

tests/models/test_models.py

@@ -25,6 +25,31 @@
 from pontos.models import Model, ModelAttribute, ModelError, dotted_attributes
 
 
+class DottedAttributesTestCase(unittest.TestCase):
+    def test_with_new_class(self):
+        class Foo:
+            pass
+
+        foo = Foo()
+        attrs = {"bar": 123, "hello": "World", "baz": [1, 2, 3]}
+
+        foo = dotted_attributes(foo, attrs)
+
+        self.assertEqual(foo.bar, 123)
+        self.assertEqual(foo.baz, [1, 2, 3])
+        self.assertEqual(foo.hello, "World")
+
+    def test_with_github_model_attribute(self):
+        foo = ModelAttribute()
+        attrs = {"bar": 123, "hello": "World", "baz": [1, 2, 3]}
+
+        foo = dotted_attributes(foo, attrs)
+
+        self.assertEqual(foo.bar, 123)
+        self.assertEqual(foo.baz, [1, 2, 3])
+        self.assertEqual(foo.hello, "World")
+
+
 class ModelTestCase(unittest.TestCase):
     def test_from_dict(self):
         model = Model.from_dict(
@@ -43,6 +68,12 @@ def test_from_dict(self):
         self.assertEqual(model.baz, [1, 2, 3])
         self.assertEqual(model.bar.a, "b")
 
+    def test_from_dict_failure(self):
+        with self.assertRaisesRegex(
+            ValueError, "Invalid data for creating an instance of.*"
+        ):
+            Model.from_dict("foo")
+
 
 class ExampleModelTestCase(unittest.TestCase):
     def test_optional(self):
@@ -165,31 +196,6 @@ class ExampleModel(Model):
         self.assertIsNotNone(model.ipsum)
         self.assertEqual(model.ipsum.something, "def")
 
-
-class DottedAttributesTestCase(unittest.TestCase):
-    def test_with_new_class(self):
-        class Foo:
-            pass
-
-        foo = Foo()
-        attrs = {"bar": 123, "hello": "World", "baz": [1, 2, 3]}
-
-        foo = dotted_attributes(foo, attrs)
-
-        self.assertEqual(foo.bar, 123)
-        self.assertEqual(foo.baz, [1, 2, 3])
-        self.assertEqual(foo.hello, "World")
-
-    def test_with_github_model_attribute(self):
-        foo = ModelAttribute()
-        attrs = {"bar": 123, "hello": "World", "baz": [1, 2, 3]}
-
-        foo = dotted_attributes(foo, attrs)
-
-        self.assertEqual(foo.bar, 123)
-        self.assertEqual(foo.baz, [1, 2, 3])
-        self.assertEqual(foo.hello, "World")
-
     def test_list_with_dict(self):
         @dataclass
         class ExampleModel(Model):
@@ -209,3 +215,23 @@ class ExampleModel(Model):
             "property 'foo' from '{'bar': 'baz'}'.",
         ):
             ExampleModel.from_dict({"foo": {"bar": "baz"}})
+
+    def test_model_error_2(self):
+        @dataclass
+        class OtherModel(Model):
+            something: str
+
+        @dataclass
+        class ExampleModel(Model):
+            foo: Optional[OtherModel]
+
+        with self.assertRaisesRegex(
+            ModelError,
+            "Error while creating ExampleModel model. Could not set value for "
+            "property 'foo' from 'abc'.",
+        ):
+            ExampleModel.from_dict(
+                {
+                    "foo": "abc",
+                }
+            )