From ed42a5817ebe93c195c01c9386feac3fcc2c5f95 Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Thu, 26 Mar 2026 13:57:21 +0100
Subject: [PATCH] DPL: more validation of MessageSet::header / payload
 replacement

---
 Framework/Core/test/test_MessageSet.cxx | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Framework/Core/test/test_MessageSet.cxx b/Framework/Core/test/test_MessageSet.cxx
index 290e55220d6cb..aa7b49c1d1d3c 100644
--- a/Framework/Core/test/test_MessageSet.cxx
+++ b/Framework/Core/test/test_MessageSet.cxx
@@ -250,6 +250,14 @@ TEST_CASE("GetHeaderPayloadOperators")
   auto& pl1 = msgSet.messages | get_payload{1, 0};
   REQUIRE(pl1.get() != nullptr);
   REQUIRE(pl1->GetSize() == 200);
+
+  // Validate pipe operators match old API
+  for (size_t i = 0; i < 2; ++i) {
+    REQUIRE(&(msgSet.messages | get_header{i}) == &msgSet.header(i));
+    REQUIRE(&(msgSet.messages | get_payload{i, 0}) == &msgSet.payload(i, 0));
+  }
+  REQUIRE((msgSet.messages | count_parts{}) == msgSet.messageMap.size());
+  REQUIRE((msgSet.messages | count_payloads{}) == msgSet.pairMap.size());
 }
 
 TEST_CASE("GetHeaderPayloadMultiPayload")