diff --git a/tests/include/test/ssl_helpers.h b/tests/include/test/ssl_helpers.h
index d03c62414b..b45e9695f7 100644
--- a/tests/include/test/ssl_helpers.h
+++ b/tests/include/test/ssl_helpers.h
@@ -193,6 +193,10 @@ typedef struct mbedtls_test_ssl_endpoint {
 
 #endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
 
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
+int rng_get(void *p_rng, unsigned char *output, size_t output_len);
+#endif
+
 /*
  * This function can be passed to mbedtls to receive output logs from it. In
  * this case, it will count the instances of a mbedtls_test_ssl_log_pattern
diff --git a/tests/src/test_helpers/ssl_helpers.c b/tests/src/test_helpers/ssl_helpers.c
index d02d305394..549a4ffc66 100644
--- a/tests/src/test_helpers/ssl_helpers.c
+++ b/tests/src/test_helpers/ssl_helpers.c
@@ -14,7 +14,7 @@
 #if defined(MBEDTLS_SSL_TLS_C)
 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
 static int rng_seed = 0xBEEF;
-static int rng_get(void *p_rng, unsigned char *output, size_t output_len)
+int rng_get(void *p_rng, unsigned char *output, size_t output_len)
 {
     (void) p_rng;
     for (size_t i = 0; i < output_len; i++) {