UserIdHelper { public static String get() { return get(SecurityUtils.getSubject()); } private  UserIdHelper(); static String get(); static String get(@Nullable final Subject subject); static boolean isSystem(); static boolean isUnknown(); static final String UNKNOWN; static final String SYSTEM; }
@Test public void get_subject() { assertThat(UserIdHelper.get(subject("test")), is("test")); }
@Test public void get_nullSubject() { assertThat(UserIdHelper.get(null), is(UNKNOWN)); }
@Test public void get_nullPrincipal() { assertThat(UserIdHelper.get(subject(null)), is(UNKNOWN)); }