@Internal
    public void initForTesting(PublicKey recipientKey, byte[] info, byte[] sKe)
        throws InvalidKeyException {
        if (sKe == null) {
            throw new IllegalArgumentException("null seed");
        }
        spi.engineInitSenderForTesting(
                recipientKey, info, null, HpkeSpi.DEFAULT_PSK, HpkeSpi.DEFAULT_PSK, sKe);
    }
Initialises this HpkeContextSender for testing in BASE mode ONLY.

@param recipientKey public key of the recipient
@param info additional application-supplied information, may be null or empty
@param sKe random seed to use during testing
@throws InvalidKeyException if recipientKey is null or an unsupported key format
@throws UnsupportedOperationException if mode is not a supported HPKE mode
@throws IllegalStateException if this HpkeContextSender has already been initialised
@throws IllegalArgumentException if sKe is null
common/src/main/java/org/conscrypt/HpkeContextSender.java