diff --git a/test/data_mock.hpp b/test/data_mock.hpp
index a79c562..44cc376 100644
--- a/test/data_mock.hpp
+++ b/test/data_mock.hpp
@@ -12,6 +12,7 @@
   public:
     virtual ~DataHandlerMock() = default;
 
+    MOCK_METHOD0(open, bool());
     MOCK_METHOD1(copyFrom, std::vector<std::uint8_t>(std::uint32_t));
     MOCK_METHOD1(write, bool(const std::vector<std::uint8_t>&));
     MOCK_METHOD0(read, std::vector<std::uint8_t>());