Base Model: modified a bit to check for lack of serialization, to gen…

…erate a standard and more informative exception if artifact or other model can't be serialized.

mlte/model/base_model.py

@@ -6,20 +6,31 @@
 
 from __future__ import annotations
 
+import json
 from typing import Any, Dict
 
 import pydantic
 
+from mlte.model.serialization_exception import SerializationException
+
 
 class BaseModel(pydantic.BaseModel):
     """The base model for all MLTE models."""
 
     def to_json(self) -> Dict[str, Any]:
         """
-        Serialize the model.
+        Serialize the model. Also check if the result is serializable.
         :return: The JSON representation of the model
         """
-        return self.model_dump()
+        json_object = self.model_dump()
+
+        # Check if object can't be serialized.
+        try:
+            _ = json.dumps(json_object)
+        except TypeError as e:
+            raise SerializationException(e, str(type(self)))
+
+        return json_object
 
     @classmethod
     def from_json(cls, data: Dict[str, Any]) -> BaseModel:

mlte/model/serialization_exception.py

@@ -0,0 +1,16 @@
+"""
+mlte/model/api/serialization_exception.py
+
+Exception used for serialization issues.
+"""
+from __future__ import annotations
+
+
+class SerializationException(TypeError):
+    """Exception used for JSON serialization issues."""
+
+    def __init__(self, error: TypeError, object: str):
+        super().__init__(
+            f"Object {object} cannot be serialized into JSON, ensure all attributes are serializable: "
+            + str(error)
+        )

test/model/test_base_model.py

@@ -0,0 +1,43 @@
+"""
+test/model/test_base_model.py
+
+Unit tests for base model functionality.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+from mlte.model.base_model import BaseModel
+from mlte.model.serialization_exception import SerializationException
+
+
+class ModelTest(BaseModel):
+    int_num: int = 1
+    float_num: float = 1.2
+    str_obj: str = "test"
+    bool_obj: bool = False
+    obj: Any = ""
+
+
+class NonSerializable:
+    attr3: str = "test"
+    attr1: dict[str, Any] = {"baz": ModelTest()}
+
+
+def test_to_json():
+    test_obj = ModelTest()
+    json_obj = test_obj.to_json()
+    reconstructed = ModelTest.from_json(json_obj)
+
+    assert test_obj == reconstructed
+
+
+def test_to_json_to_str_not_serializable():
+    test_obj = ModelTest()
+    test_obj.obj = NonSerializable()
+
+    with pytest.raises(SerializationException):
+        _ = test_obj.to_json()