### Question:
JwtUtil { public String getUsernameFromToken(String token) { return getClaimsFromToken(token).getSubject(); }  String generateToken(User user, boolean isRemember); Boolean validateToken(String token, User user); Boolean isTokenExpired(String token); String getUsernameFromToken(String token); Date getExpirationDateFromToken(String token); static final long EXPIRATION_LONG_TIME; static final long EXPIRATION_SHORT_TIME; }### Answer:
@Test public void getUsernameFromToken() { assertEquals("a@celess.cn", jwtUtil.getUsernameFromToken(createToken())); }