Implement minimal consumer to exhibit failure

test/k4FWCoreTest/CMakeLists.txt

@@ -112,3 +112,4 @@ add_test_with_env(ExampleFunctionalConsumerMultiple options/runExampleFunctional
 add_test_with_env(ExampleFunctionalTransformerMultiple options/runExampleFunctionalTransformerMultiple.py PROPERTIES DEPENDS ExampleFunctionalProducerMultiple)
 add_test_with_env(FunctionalChain options/runFunctionalChain.py)
 add_test_with_env(FunctionalMix options/runFunctionalMix.py PROPERTIES DEPENDS ExampleFunctionalProducerMultiple)
+add_test_with_env(EventHeaderCheck options/runEventHeaderCheck.py PROPERTIES DEPENDS ExampleFunctionalProducerMultiple)

test/k4FWCoreTest/options/runEventHeaderCheck.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2014-2023 Key4hep-Project.
+#
+# This file is part of Key4hep.
+# See https://key4hep.github.io/key4hep-doc/ for further info.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from Gaudi.Configuration import INFO
+from Configurables import k4DataSvc
+from Configurables import PodioInput
+from Configurables import ExampleEventHeaderConsumer
+from Configurables import ApplicationMgr
+
+podioevent = k4DataSvc("EventDataSvc")
+podioevent.input = "output_k4test_exampledata_producer_multiple.root"
+
+inp = PodioInput()
+inp.collections = []
+
+consumer = ExampleEventHeaderConsumer()
+
+ApplicationMgr(
+    TopAlg=[inp, consumer],
+    EvtSel="NONE",
+    EvtMax=-1,
+    ExtSvc=[podioevent],
+    OutputLevel=INFO,
+)

test/k4FWCoreTest/src/components/ExampleEventHeaderConsumer.cpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2014-2023 Key4hep-Project.
+ *
+ * This file is part of Key4hep.
+ * See https://key4hep.github.io/key4hep-doc/ for further info.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <GaudiKernel/ISvcLocator.h>
+#include "GaudiAlg/Consumer.h"
+
+#include "edm4hep/Constants.h"
+#include "edm4hep/EventHeaderCollection.h"
+
+#include "k4FWCore/BaseClass.h"
+
+#include <optional>
+#include <stdexcept>
+
+struct ExampleEventHeaderConsumer final
+    : Gaudi::Functional::Consumer<void(std::optional<const edm4hep::EventHeaderCollection&>), BaseClass_t> {
+  ExampleEventHeaderConsumer(const std::string& name, ISvcLocator* svcLoc)
+      : Consumer(name, svcLoc, {KeyValue("EventHeaderName", edm4hep::EventHeaderName)}) {}
+
+  void operator()(const edm4hep::EventHeaderCollection& evtHeaderColl) const {
+    if (evtHeaderColl.empty()) {
+      throw std::runtime_error("EventHeader collection is empty");
+    }
+    if (!evtHeaderColl[0].isAvailable()) {
+      throw std::runtime_error("Cannot get a valid EventHeader");
+    }
+  }
+};
+
+DECLARE_COMPONENT(ExampleEventHeaderConsumer)