diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index a7baec66de..34164a83fc 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -7,6 +7,12 @@
 #include "mbedtls/oid.h"
 #include "mbedtls/base64.h"
 
+#if MBEDTLS_X509_MAX_INTERMEDIATE_CA >= 19
+#error "The value of MBEDTLS_X509_MAX_INTERMEDIATE_C is larger \
+than the current threshold 19. To test larger values, please \
+adapt the script tests/data_files/dir-max/long.sh."
+#endif
+
 /* Profile for backward compatibility. Allows SHA-1, unlike the default
    profile. */
 const mbedtls_x509_crt_profile compat_profile =