### Question:
ProxyAuthentication implements Serializable { public static Builder builder() { return new Builder(); } private  ProxyAuthentication(String userName, String password); static Builder builder(); String getUserName(); String getPassword();  }### Answer:
@Test(expected = IllegalArgumentException.class) public void testBuilderShouldThrowIllegalArgumentExcepitonWhenPasswordNotProvided() { ProxyAuthentication.builder() .withUserName("user") .withPassword("") .build(); }
@Test(expected = IllegalArgumentException.class) public void testBuilderShouldThrowIllegalArgumentExcepitonWhenUserNameNotProvided() { ProxyAuthentication.builder() .withUserName(null) .withPassword("pwd") .build(); }