### Question:
TokenDetails { public String getMaskedRefreshToken() { return getMaskedString(refreshToken, 7); } TokenDetails();  TokenDetails(String accessToken, String refreshToken, LocalDateTime accessTokenExpiration); String getAccessToken(); void setAccessToken(String accessToken); String getRefreshToken(); void setRefreshToken(String refreshToken); LocalDateTime getAccessTokenExpiration(); void setAccessTokenExpiration(LocalDateTime accessTokenExpiration); Class getCredentialsProvider(); void setCredentialsProvider(Class credentialsProvider); String getRealm(); void setRealm(String realm); boolean isEmpty(); boolean isNotEmpty(); String getMaskedAccessToken(); String getMaskedRefreshToken(); String getAccessExpiredIn(); void setAccessExpiredIn(String accessExpiredIn); String getRefreshExpiredIn(); void setRefreshExpiredIn(String refreshExpiredIn); @Override String toString();  }### Answer:
@Test void getMaskedRefreshToken() { TokenDetails tokenDetails = new TokenDetails(); assertThat(tokenDetails.getMaskedRefreshToken(), is(nullValue())); tokenDetails.setRefreshToken("0123456789"); assertThat(tokenDetails.getMaskedRefreshToken(), is("*****3456789")); }