diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index b11a7d0bf..7cdd2e187 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -1,12 +1,12 @@
 /* BEGIN_HEADER */
 #include <polarssl/ctr_drbg.h>
 
-int test_offset;
+int test_offset_idx;
 int entropy_func( void *data, unsigned char *buf, size_t len )
 {
     unsigned char *p = (unsigned char *) data;
-    memcpy( buf, p + test_offset, len );
-    test_offset += 32;
+    memcpy( buf, p + test_offset_idx, len );
+    test_offset_idx += 32;
     return( 0 );
 }
 /* END_HEADER */
@@ -37,7 +37,7 @@ void ctr_drbg_validate_pr( char *add_init_string, char *entropy_string,
     add1_len = unhexify( add1, add1_string );
     add2_len = unhexify( add2, add2_string );
 
-    test_offset = 0;
+    test_offset_idx = 0;
     TEST_ASSERT( ctr_drbg_init_entropy_len( &ctx, entropy_func, entropy, add_init, add_init_len, 32 ) == 0 );
     ctr_drbg_set_prediction_resistance( &ctx, CTR_DRBG_PR_ON );
 
@@ -71,7 +71,7 @@ void ctr_drbg_validate_nopr( char *add_init_string, char *entropy_string,
     add_reseed_len = unhexify( add_reseed, add_reseed_string );
     add2_len = unhexify( add2, add2_string );
 
-    test_offset = 0;
+    test_offset_idx = 0;
     TEST_ASSERT( ctr_drbg_init_entropy_len( &ctx, entropy_func, entropy, add_init, add_init_len, 32 ) == 0 );
 
     TEST_ASSERT( ctr_drbg_random_with_add( &ctx, buf, 16, add1, add1_len ) == 0 );