diff --git a/test/io_mock.hpp b/test/io_mock.hpp
new file mode 100644
index 0000000..2cff9a8
--- /dev/null
+++ b/test/io_mock.hpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include "io.hpp"
+
+#include <gmock/gmock.h>
+
+namespace host_tool
+{
+
+class HostIoInterfaceMock : public HostIoInterface
+{
+  public:
+    ~HostIoInterfaceMock() = default;
+
+    MOCK_METHOD3(write,
+                 bool(const std::size_t, const std::size_t, const void* const));
+};
+
+} // namespace host_tool