tests: Rename Gateway.handle_upload() test & move bottle.response mock to conftest.py fixture

Gateway.handle_upload: Rename function to include 'valid'

src/tests/conftest.py

@@ -77,3 +77,12 @@ def eddn_gateway():
     eddn.Gateway.configure()
 
     return eddn.Gateway
+
+
+@pytest.fixture
+def bottle_response() -> object:
+    """Mock a `bottle.response` enough for tests."""
+    class BottleResponseMock:
+        status: int = 200
+
+    return BottleResponseMock()

src/tests/gateway/test_handle_upload.py

@@ -2,7 +2,12 @@
 from typing import Callable
 
 
-def test_plain_message(fix_sys_path, eddn_gateway, eddn_message: Callable) -> None:
+def test_valid_plain_message(
+    fix_sys_path,
+    eddn_message: Callable,
+    eddn_gateway,
+    bottle_response
+) -> None:
     """Test eddn.Gateway with a plain message."""
     ####################################################################
     # Mock a bottle 'response' enough to accept setting status
@@ -17,7 +22,7 @@ def test_plain_message(fix_sys_path, eddn_gateway, eddn_message: Callable) -> No
             "Content-Type": "application/json"
         },
         body=msg.encode(encoding="utf-8"),
-        response=BottleResponseMock()
+        response=bottle_response
     )
 
     print(f"{resp_str=}")