diff --git a/src/tests/gateway/test_handle_upload.py b/src/tests/gateway/test_handle_upload.py
new file mode 100644
index 0000000..35f3a4b
--- /dev/null
+++ b/src/tests/gateway/test_handle_upload.py
@@ -0,0 +1,24 @@
+"""Test Gateway.handle_upload()."""
+from typing import Callable
+
+
+def test_plain_message(fix_sys_path, eddn_gateway, eddn_message: Callable) -> None:
+    """Test eddn.Gateway with a plain message."""
+    ####################################################################
+    # Mock a bottle 'response' enough to accept setting status
+    ####################################################################
+    class BottleResponseMock:
+        status: int = 200
+    ####################################################################
+
+    msg = eddn_message("plain_journal_scan_valid")
+    resp_str = eddn_gateway.handle_upload(
+        headers={
+            "Content-Type": "application/json"
+        },
+        body=msg.encode(encoding="utf-8"),
+        response=BottleResponseMock()
+    )
+
+    print(f"{resp_str=}")
+    assert resp_str.startswith("OK")