Document MBEDTLS_ALLOW_PRIVATE_ACCESS inside test/helpers.h.
#ifndef TEST_HELPERS_H
#define TEST_HELPERS_H
+/* Most fields of publicly available structs are private and are wrapped with
+ * MBEDTLS_PRIVATE macro. This define allows tests to access the private fields
+ * directly (without using the MBEDTLS_PRIVATE wrapper). */
#define MBEDTLS_ALLOW_PRIVATE_ACCESS
#if !defined(MBEDTLS_CONFIG_FILE)
