diff --git a/tests/suites/test_suite_hkdf.function b/tests/suites/test_suite_hkdf.function
index fc0e24217..d2d66596f 100644
--- a/tests/suites/test_suite_hkdf.function
+++ b/tests/suites/test_suite_hkdf.function
@@ -20,10 +20,10 @@ void test_hkdf( int md_alg, char *hex_ikm_string, char *hex_salt_string,
     unsigned char expected_okm[128] = { '\0' };
     unsigned char okm[128] = { '\0' };
     /*
-     * okm_string is the string representation of okm,
-     * so its size is twice as the size of okm.
+     * okm_hex is the string representation of okm,
+     * so its size is twice the size of okm.
      */
-    unsigned char okm_string[256] = { '\0' };
+    unsigned char okm_hex[256] = { '\0' };
 
     const mbedtls_md_info_t *md = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md != NULL );
@@ -38,8 +38,8 @@ void test_hkdf( int md_alg, char *hex_ikm_string, char *hex_salt_string,
     TEST_ASSERT( ret == 0 );
 
     // Run hexify on it so that it looks nicer if the assertion fails
-    hexify( okm_string, okm, okm_len );
-    TEST_ASSERT( !strcmp( (char *)okm_string, hex_okm_string ) );
+    hexify( okm_hex, okm, okm_len );
+    TEST_ASSERT( !strcmp( (char *)okm_hex, hex_okm_string ) );
 }
 /* END_CASE */