diff --git a/src/gpioplus/test/sys.hpp b/src/gpioplus/test/sys.hpp
new file mode 100644
index 0000000..c794218
--- /dev/null
+++ b/src/gpioplus/test/sys.hpp
@@ -0,0 +1,32 @@
+#pragma once
+#include <gmock/gmock.h>
+#include <gpioplus/internal/sys.hpp>
+
+namespace gpioplus
+{
+namespace test
+{
+
+class SysMock : public internal::Sys
+{
+  public:
+    MOCK_CONST_METHOD2(open, int(const char*, int));
+    MOCK_CONST_METHOD1(dup, int(int));
+    MOCK_CONST_METHOD1(close, int(int));
+    MOCK_CONST_METHOD3(read, int(int, void*, size_t));
+    MOCK_CONST_METHOD2(fcntl_setfl, int(int, int));
+    MOCK_CONST_METHOD1(fcntl_getfl, int(int));
+
+    MOCK_CONST_METHOD2(gpiohandle_get_line_values,
+                       int(int, struct gpiohandle_data*));
+    MOCK_CONST_METHOD2(gpiohandle_set_line_values,
+                       int(int, struct gpiohandle_data*));
+    MOCK_CONST_METHOD2(gpio_get_chipinfo, int(int, struct gpiochip_info*));
+    MOCK_CONST_METHOD2(gpio_get_lineinfo, int(int, struct gpioline_info*));
+    MOCK_CONST_METHOD2(gpio_get_linehandle,
+                       int(int, struct gpiohandle_request*));
+    MOCK_CONST_METHOD2(gpio_get_lineevent, int(int, struct gpioevent_request*));
+};
+
+} // namespace test
+} // namespace gpioplus