fix: validate player squad numbers

models/player_model.py

@@ -5,7 +5,7 @@
 - `PlayerRequestModel`: Represents player data for Create and Update operations.
 - `PlayerResponseModel`: Represents player data including UUID for Retrieve operations.
 
-Design decision — single request model vs split models:
+Design decision - single request model vs split models:
     A single `PlayerRequestModel` is intentionally shared by both POST (Create)
     and PUT (Update). Per-operation differences are handled at the route layer
     rather than by duplicating the model:
@@ -19,7 +19,7 @@
 
 from typing import Optional
 from uuid import UUID
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field
 from pydantic.alias_generators import to_camel
 
 
@@ -53,7 +53,8 @@ class PlayerRequestModel(MainModel):
         middle_name (Optional[str]): The middle name of the Player, if any.
         last_name (str): The last name of the Player.
         date_of_birth (Optional[str]): The date of birth of the Player, if provided.
-        squad_number (int): The unique squad number assigned to the Player.
+        squad_number (int): The unique, positive squad number assigned to the
+        Player.
         position (str): The playing position of the Player.
         abbr_position (Optional[str]): The abbreviated form of the Player's position,
         if any.
@@ -67,7 +68,7 @@ class PlayerRequestModel(MainModel):
     middle_name: Optional[str] = None
     last_name: str
     date_of_birth: Optional[str] = None
-    squad_number: int
+    squad_number: int = Field(gt=0)
     position: str
     abbr_position: Optional[str] = None
     team: Optional[str] = None

tests/test_main.py

@@ -190,6 +190,19 @@ def test_request_post_player_body_existing_response_body_detail(client):
     )
 
 
+def test_request_post_player_body_zero_squad_number_response_status_unprocessable(
+    client,
+):
+    """POST /players/ with squad number zero returns 422 Unprocessable Entity"""
+    # Arrange
+    player = nonexistent_player()
+    payload = player.__dict__ | {"squad_number": 0}
+    # Act
+    response = client.post(PATH, json=payload)
+    # Assert
+    assert response.status_code == 422
+
+
 def test_request_post_player_body_nonexistent_response_status_created(client):
     """POST /players/ with nonexistent player returns 201 Created with a valid UUID"""
     # Arrange
@@ -203,7 +216,7 @@ def test_request_post_player_body_nonexistent_response_status_created(client):
         assert "id" in body
         assert UUID(body["id"]).version == 4  # UUID v4 (API-created)
     finally:
-        # Teardown — remove the created player
+        # Teardown - remove the created player
         client.delete(PATH + "squadnumber/" + str(player.squad_number))
 
 
@@ -250,7 +263,7 @@ def test_request_put_player_squadnumber_existing_response_status_no_content(clie
         # Assert
         assert response.status_code == 204
     finally:
-        # Teardown — restore Damián Martínez to its seeded state
+        # Teardown - restore Damián Martínez to its seeded state
         seed = existing_player()
         client.put(PATH + "squadnumber/" + str(seed.squad_number), json=seed.__dict__)