diff --git a/src/gy521_driver/gy521_driver.c b/src/gy521_driver/gy521_driver.c
index 0e2d1e4..533e74d 100644
--- a/src/gy521_driver/gy521_driver.c
+++ b/src/gy521_driver/gy521_driver.c
@@ -22,6 +22,14 @@ extern void _test_free(void* const ptr, const char* file, const int line);
 #define malloc(size) _test_malloc(size, __FILE__, __LINE__)
 #define calloc(num, size) _test_calloc(num, size, __FILE__, __LINE__)
 #define free(ptr) _test_free(ptr, __FILE__, __LINE__)
+
+/*Mock assertions: redefines assert() calls*/
+extern void mock_assert(const int result, const char* const expression, 
+                        const char * const file, const int line);
+#undef assert
+#define assert(expression) \
+    mock_assert((int)(expression), #expression, __FILE__, __LINE__);
+
 #endif // UNIT_TESTING
 
 #define     NUM_ACCEL_REGS  6
@@ -324,6 +332,7 @@ struct ft_vals self_test_ft_calculation(struct gy521_module* m)
 /*Self Test register functions*/
 self_test_results gy521_self_test(struct gy521_module* m)
 {
+
     /*0. Enable self test*/
     enable_self_test_gyro(m);