diff --git a/tests/unit/testempty1.c b/tests/unit/testempty1.c
index 01547e3d..f4140f64 100644
--- a/tests/unit/testempty1.c
+++ b/tests/unit/testempty1.c
@@ -58,7 +58,7 @@ int main(int argc, char *argv[])
 
   const OPJ_COLOR_SPACE color_space = OPJ_CLRSPC_GRAY;
   unsigned int numcomps = 1;
-  int i;
+  unsigned int i;
   unsigned int image_width = 256;
   unsigned int image_height = 256;
 
diff --git a/tests/unit/testempty2.c b/tests/unit/testempty2.c
index dbbbaf93..764b14cc 100644
--- a/tests/unit/testempty2.c
+++ b/tests/unit/testempty2.c
@@ -59,7 +59,7 @@ int main(int argc, char *argv[])
 
   const OPJ_COLOR_SPACE color_space = OPJ_CLRSPC_GRAY;
   unsigned int numcomps = 1;
-  int i;
+  unsigned int i;
   unsigned int image_width = 256;
   unsigned int image_height = 256;