feat: add tests for requests with empty body

Author: tonnico

tests/functional/event_handler/_pydantic/test_openapi_validation_middleware.py

@@ -366,6 +366,53 @@ def handler(user: Annotated[Model, Body(embed=True)]) -> Model:
     assert result["statusCode"] == 200
 
 
+def test_validate_body_params_with_missing_body_sets_received_body_none(gw_event):
+    # GIVEN an APIGatewayRestResolver with validation enabled
+    app = APIGatewayRestResolver(enable_validation=True)
+
+    # WHEN a handler is defined with multiple body parameters
+    @app.post("/")
+    def handler(name: str, age: int):
+        return {"name": name, "age": age}
+
+    # WHEN the event has no body
+    gw_event["httpMethod"] = "POST"
+    gw_event["path"] = "/"
+    gw_event["body"] = None  # simulate event without body
+    gw_event["headers"]["content-type"] = "application/json"
+
+    result = app(gw_event, {})
+
+    # THEN the handler should be invoked and return 422
+    assert result["statusCode"] == 422
+    assert "missing" in result["body"]
+
+
+def test_validate_embed_body_param_with_missing_body_sets_received_body_none(gw_event):
+    # GIVEN an APIGatewayRestResolver with validation enabled
+    app = APIGatewayRestResolver(enable_validation=True)
+
+    class Model(BaseModel):
+        name: str
+
+    # WHEN a handler is defined with a body parameter
+    @app.post("/")
+    def handler(user: Annotated[Model, Body(embed=True)]) -> Model:
+        return user
+
+    # WHEN the event has no body
+    gw_event["httpMethod"] = "POST"
+    gw_event["path"] = "/"
+    gw_event["body"] = None  # simulate event without body
+    gw_event["headers"]["content-type"] = "application/json"
+
+    result = app(gw_event, {})
+
+    # THEN the handler should be invoked and return 422
+    assert result["statusCode"] == 422
+    assert "missing" in result["body"]
+
+
 def test_validate_response_return(gw_event):
     # GIVEN an APIGatewayRestResolver with validation enabled
     app = APIGatewayRestResolver(enable_validation=True)