default or selected kernelversion does not have config value CONFIG_CRYPTO_LIB_CURVE25519_KUNIT_TEST.
Result is shown for kernelversion 6.18-rc3

KUnit tests for Curve25519

modulename: curve25519_kunit.ko

configname: CONFIG_CRYPTO_LIB_CURVE25519_KUNIT_TEST

Linux Kernel Configuration
└─>Library routines
└─>Crypto library routines
└─>KUnit tests for Curve25519
KUnit tests for the Curve25519 Diffie-Hellman function.

source code:
lib/crypto//tests/curve25519_kunit.c

depends
CONFIG_KUNIT