### Question:
JwsJsonProducer { public String getUnsignedEncodedPayload() { if (encodedPayload == null) { encodedPayload = Base64UrlUtility.encode(getPlainPayload()); } return encodedPayload; } JwsJsonProducer(String tbsDocument);  JwsJsonProducer(String tbsDocument, boolean supportFlattened);  JwsJsonProducer(String tbsDocument, boolean supportFlattened, boolean supportDetached); String getPlainPayload(); String getUnsignedEncodedPayload(); String getJwsJsonSignedDocument(); @Deprecated String getJwsJsonSignedDocument(boolean detached); List<JwsJsonSignatureEntry> getSignatureEntries(); String signWith(List<JwsSignatureProvider> signers); String signWith(JwsSignatureProvider signer); String signWith(JwsSignatureProvider signer,
                           JwsHeaders protectedHeader); String signWith(JsonWebKey jwk); String signWith(PrivateKey key, SignatureAlgorithm algo); String signWith(byte[] key, SignatureAlgorithm algo); String signWith(JwsSignatureProvider signer,
                           JwsHeaders protectedHeader,
                           JwsHeaders unprotectedHeader);  }### Answer:
@Test public void testSignPlainJsonDocumentPayloadConstruction() { JwsJsonProducer producer = new JwsJsonProducer(UNSIGNED_PLAIN_JSON_DOCUMENT); assertEquals(UNSIGNED_PLAIN_JSON_DOCUMENT_AS_B64URL, producer.getUnsignedEncodedPayload()); }