python 3.8 and pydantic 1 compat

tests/test_forms_defaults.py

@@ -1,17 +1,21 @@
-from typing import Annotated, Optional
+from importlib.metadata import version
+from typing import Optional
 
 import pytest
 from fastapi import FastAPI, Form
-from pydantic import BaseModel, Field, model_validator
+from pydantic import BaseModel, Field
 from starlette.testclient import TestClient
+from typing_extensions import Annotated
 
+PYDANTIC_V2 = int(version("pydantic")[0]) >= 2
 
-class Parent(BaseModel):
-    init_input: dict
-    # importantly, no default here
+if PYDANTIC_V2:
+    from pydantic import model_validator
+else:
+    from pydantic import root_validator
 
-    @model_validator(mode="before")
-    def validate_inputs(cls, value: dict) -> dict:
+
+def _validate_input(value: dict) -> dict:
     """
     model validators in before mode should receive values passed
     to model instantiation before any further validation
@@ -26,6 +30,22 @@ class Parent(BaseModel):
     return value
 
 
+class Parent(BaseModel):
+    init_input: dict
+    # importantly, no default here
+
+    if PYDANTIC_V2:
+
+        @model_validator(mode="before")
+        def validate_inputs(cls, value: dict) -> dict:
+            return _validate_input(value)
+    else:
+
+        @root_validator(pre=True)
+        def validate_inputs(cls, value: dict) -> dict:
+            return _validate_input(value)
+
+
 class StandardModel(Parent):
     default_true: bool = True
     default_false: bool = False