### Question:
PayloadImpl implements Payload, Serializable { @Override public Date getExpiresAt() { return expiresAt; } PayloadImpl(String issuer, String subject, List<String> audience, Date expiresAt, Date notBefore, Date issuedAt, String jwtId, Map<String, JsonNode> tree, ObjectReader objectReader); @Override String getIssuer(); @Override String getSubject(); @Override List<String> getAudience(); @Override Date getExpiresAt(); @Override Date getNotBefore(); @Override Date getIssuedAt(); @Override String getId(); @Override Claim getClaim(String name); @Override Map<String, Claim> getClaims();  }### Answer:
@Test public void shouldGetExpiresAt() throws Exception { assertThat(payload, is(notNullValue())); assertThat(payload.getExpiresAt(), is(expiresAt)); }
@Test public void shouldGetNullExpiresAtIfMissing() throws Exception { PayloadImpl payload = new PayloadImpl(null, null, null, null, null, null, null, null, objectReader); assertThat(payload, is(notNullValue())); assertThat(payload.getExpiresAt(), is(nullValue())); }