diff --git a/test/internal_sys_mock.hpp b/test/internal_sys_mock.hpp
index 42abe2f..2225203 100644
--- a/test/internal_sys_mock.hpp
+++ b/test/internal_sys_mock.hpp
@@ -23,6 +23,7 @@
     MOCK_CONST_METHOD6(mmap, void*(void*, size_t, int, int, int, off_t));
     MOCK_CONST_METHOD2(munmap, int(void*, size));
     MOCK_CONST_METHOD0(getpagesize, int());
+    MOCK_CONST_METHOD3(ioctl, int(int, unsigned long, void*));
 };
 
 } // namespace internal