diff --git a/unit_tests/test_basic_math/test_find_index.cpp b/unit_tests/test_basic_math/test_find_index.cpp
index b961324fa6..238faabe8b 100644
--- a/unit_tests/test_basic_math/test_find_index.cpp
+++ b/unit_tests/test_basic_math/test_find_index.cpp
@@ -10,7 +10,7 @@
 #include "interpolation.h"
 #include "unit_test_framework.h"
 
-static int testIndex(const int expected, const float array[], int size, float value) {
+static void testIndex(const int expected, const float array[], int size, float value) {
 	assertEquals(expected, findIndex(array, size, value));
 	assertEquals(expected, findIndex2(array, size, value));
 }