diff --git a/phosphor-logging/test/sdjournal_mock.hpp b/phosphor-logging/test/sdjournal_mock.hpp
index 3290480..b907bcc 100644
--- a/phosphor-logging/test/sdjournal_mock.hpp
+++ b/phosphor-logging/test/sdjournal_mock.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdarg>
 #include <phosphor-logging/sdjournal.hpp>
 
 #include <gmock/gmock.h>
@@ -9,7 +10,7 @@
 namespace logging
 {
 
-class SdJournalMock : public SdJournalImpl
+class SdJournalMock : public SdJournalHandler
 {
   public:
     virtual ~SdJournalMock() = default;
@@ -18,10 +19,11 @@
     MOCK_METHOD1(journal_send_call, int(const char*));
 
     int journal_send(const char* fmt, ...) override
+        __attribute__((format(printf, 2, 0))) __attribute__((sentinel))
     {
         return journal_send_call(fmt);
     }
-}
+};
 
 } // namespace logging
 } // namespace phosphor