then:
        // since the key is not fully validated until needed, we only get an error when encrypting
        failure.assertHasDescription("Error loading encryption key from GRADLE_ENCRYPTION_KEY environment variable")
        failure.assertHasCause("Illegal base64 character ${Integer.toHexString((int) invalidBase64Char)}")
    }

    def "build fails if key is provided via env var but not long enough"() {

    override val sourceDescription: String
        get() = "$GRADLE_ENCRYPTION_KEY_ENV_KEY environment variable"

    companion object {
        const val GRADLE_ENCRYPTION_KEY_ENV_KEY = "GRADLE_ENCRYPTION_KEY"
    }
}


private
class NoEncryptionKeySource : SecretKeySource {
    override fun getKey(): SecretKey? {
        logger.warn("Encryption of the configuration cache is disabled.")

====

[[config_cache:secrets:generating_encryption_key]]
=== Generating an encryption key that is compatible with GRADLE_ENCRYPTION_KEY

For Gradle to encrypt the configuration cache using a user-specified encryption key,
you must run Gradle while having the GRADLE_ENCRYPTION_KEY environment variable set with a valid AES key, encoded as a Base64 string.