diff --git a/tests/suites/test_suite_base64.function b/tests/suites/test_suite_base64.function
index 53f38bf..ab6d88c 100644
--- a/tests/suites/test_suite_base64.function
+++ b/tests/suites/test_suite_base64.function
@@ -13,13 +13,13 @@
 {
     unsigned char src_str[1000];
     unsigned char dst_str[1000];
-    size_t len = dst_buf_size;
+    size_t len;
 
     memset(src_str, 0x00, 1000);
     memset(dst_str, 0x00, 1000);
 
     strncpy( (char *) src_str, src_string, sizeof(src_str) - 1 );
-    TEST_ASSERT( mbedtls_base64_encode( dst_str, &len, src_str, strlen( (char *) src_str ) ) == result );
+    TEST_ASSERT( mbedtls_base64_encode( dst_str, dst_buf_size, &len, src_str, strlen( (char *) src_str ) ) == result );
     if( result == 0 )
     {
         TEST_ASSERT( strcmp( (char *) dst_str, dst_string ) == 0 );
@@ -32,14 +32,14 @@
 {
     unsigned char src_str[1000];
     unsigned char dst_str[1000];
-    size_t len = 1000;
+    size_t len;
     int res;
 
     memset(src_str, 0x00, 1000);
     memset(dst_str, 0x00, 1000);
 
     strncpy( (char *) src_str, src_string, sizeof(src_str) - 1 );
-    res = mbedtls_base64_decode( dst_str, &len, src_str, strlen( (char *) src_str ) );
+    res = mbedtls_base64_decode( dst_str, sizeof( dst_str ), &len, src_str, strlen( (char *) src_str ) );
     TEST_ASSERT( res == result );
     if( result == 0 )
     {
@@ -53,12 +53,12 @@
                         int result )
 {
     unsigned char *src = NULL, *res = NULL;
-    size_t len = dst_buf_size, src_len;
+    size_t len, src_len;
 
     src = unhexify_alloc( src_hex, &src_len );
     res = zero_alloc( dst_buf_size );
 
-    TEST_ASSERT( mbedtls_base64_encode( res, &len, src, src_len ) == result );
+    TEST_ASSERT( mbedtls_base64_encode( res, dst_buf_size, &len, src, src_len ) == result );
     if( result == 0 )
     {
         TEST_ASSERT( len == strlen( dst ) );
@@ -76,12 +76,12 @@
                         int result )
 {
     unsigned char *dst = NULL, *res = NULL;
-    size_t len = dst_buf_size, dst_len;
+    size_t len, dst_len;
 
     dst = unhexify_alloc( dst_hex, &dst_len );
     res = zero_alloc( dst_buf_size );
 
-    TEST_ASSERT( mbedtls_base64_decode( res, &len, (unsigned char *) src,
+    TEST_ASSERT( mbedtls_base64_decode( res, dst_buf_size, &len, (unsigned char *) src,
                                 strlen( src ) ) == result );
     if( result == 0 )
     {
@@ -104,8 +104,7 @@
 
     src = unhexify_alloc( src_hex, &src_len );
 
-    len = sizeof( dst );
-    TEST_ASSERT( mbedtls_base64_decode( dst, &len, src, src_len ) == result );
+    TEST_ASSERT( mbedtls_base64_decode( dst, sizeof( dst ), &len, src, src_len ) == result );
     if( result == 0 )
     {
         TEST_ASSERT( len == strlen( dst_ref ) );