Added doc and test for JSON overwrite of url params

Author: Seluj78

flask_utils/decorators.py

@@ -225,6 +225,33 @@ def example(name: str, age: int, is_student: bool, courses: List[str], grades: D
             * Optional
             * Union
 
+    .. warning::
+        If a parameter exists both in the route parameters and in the JSON body,
+        the value from the JSON body will override the route parameter. A warning
+        is issued when this occurs.
+
+        :Example:
+
+        .. code-block:: python
+
+            from flask import Flask, request
+            from typing import List, Dict
+            from flask_utils.decorators import validate_params
+            from flask_utils.errors import BadRequestError
+
+            app = Flask(__name__)
+
+            @app.route("/users/<int:user_id>", methods=["POST"])
+            @validate_params()
+            def create_user(user_id: int):
+                print(f"User ID: {user_id}")
+                return "User created"
+
+            ...
+
+            requests.post("/users/123", json={"user_id": 456})
+            # Output: User ID: 456
+
     .. versionchanged:: 1.0.0
         The decorator doesn't take any parameters anymore,
         it loads the types and parameters from the function signature as well as the Flask route's slug parameters.

tests/test_validate_params.py

@@ -565,3 +565,17 @@ def test_max_depth(self, client):
             assert len(w) == 1
             assert issubclass(w[-1].category, SyntaxWarning)
             assert "Maximum depth of 4 reached." in str(w[-1].message)
+
+
+class TestJSONOverridesRouteParams:
+    @pytest.fixture(autouse=True)
+    def setup_routes(self, flask_client):
+        @flask_client.post("/users/<int:user_id>")
+        @validate_params()
+        def create_user(user_id: int):
+            return f"{user_id}"
+
+    def test_valid_request(self, client):
+        response = client.post("/users/123", json={"user_id": 456})
+        assert response.status_code == 200
+        assert response.text == "456"