diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index f9e9093..0f4e313 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -4,6 +4,7 @@
 #include "mbedtls/asn1.h"
 #include "mbedtls/asn1write.h"
 #include "mbedtls/oid.h"
+#include "common.h"
 
 /* For MBEDTLS_CTR_DRBG_MAX_REQUEST, knowing that psa_generate_random()
  * uses mbedtls_ctr_drbg internally. */
@@ -2658,7 +2659,7 @@
     TEST_LE_U( length, output_buffer_size );
     output_length += length;
     PSA_ASSERT( psa_cipher_finish( &operation,
-                                   output + output_length,
+                                   mbedtls_buffer_offset( output, output_length ),
                                    output_buffer_size - output_length,
                                    &length ) );
     output_length += length;
@@ -2676,7 +2677,7 @@
     TEST_LE_U( length, output_buffer_size );
     output_length += length;
     PSA_ASSERT( psa_cipher_finish( &operation,
-                                   output + output_length,
+                                   mbedtls_buffer_offset( output, output_length ),
                                    output_buffer_size - output_length,
                                    &length ) );
     output_length += length;