Combine hex parameters in a struct
diff --git a/tests/suites/test_suite_pem.function b/tests/suites/test_suite_pem.function
index 222d581..dcd53d6 100644
--- a/tests/suites/test_suite_pem.function
+++ b/tests/suites/test_suite_pem.function
@@ -6,21 +6,21 @@
 /* END_HEADER */
 
 /* BEGIN_CASE depends_on:MBEDTLS_PEM_WRITE_C */
-void mbedtls_pem_write_buffer( char * start, char * end, uint8_t * buf,
-                               uint32_t buf_len, char * result_str )
+void mbedtls_pem_write_buffer( char * start, char * end, HexParam_t * buf,
+                               char * result_str )
 {
     unsigned char *check_buf = NULL;
     int ret;
     size_t olen = 0, olen2 = 0;
 
 
-    ret = mbedtls_pem_write_buffer( start, end, buf, buf_len, NULL, 0, &olen );
+    ret = mbedtls_pem_write_buffer( start, end, buf->x, buf->len, NULL, 0, &olen );
     TEST_ASSERT( ret == MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
 
     check_buf = (unsigned char *) mbedtls_calloc( 1, olen );
     TEST_ASSERT( check_buf != NULL );
 
-    ret = mbedtls_pem_write_buffer( start, end, buf, buf_len, check_buf, olen, &olen2 );
+    ret = mbedtls_pem_write_buffer( start, end, buf->x, buf->len, check_buf, olen, &olen2 );
 
     TEST_ASSERT( olen2 <= olen );
     TEST_ASSERT( olen > strlen( (char*) result_str ) );