diff --git a/rw_core/flow_decomposition/flow_decomposer_test.go b/rw_core/flow_decomposition/flow_decomposer_test.go
index 42e42e6..41a93e4 100644
--- a/rw_core/flow_decomposition/flow_decomposer_test.go
+++ b/rw_core/flow_decomposition/flow_decomposer_test.go
@@ -137,6 +137,10 @@
 	return nil
 }
 
+func (tdm *testDeviceManager) MarkChildDevicesAsUnReachable(cDevice *voltha.Device) error {
+	return nil
+}
+
 type testFlowDecomposer struct {
 	dMgr         *testDeviceManager
 	logicalPorts map[uint32]*voltha.LogicalPort