Fix another wrong check for errors in test code
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 1c5f67c..f1a793b 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -789,7 +789,7 @@
 
     /* Allocate second buffer and serialise to it */
     buf2 = mbedtls_calloc( 1, len0 );
-    TEST_ASSERT( buf1 != NULL );
+    TEST_ASSERT( buf2 != NULL );
     TEST_ASSERT( mbedtls_ssl_session_save( &session, buf2, len0, &len2 )
                  == 0 );