CacheHeader { public static void setExpiresDays(@NotNull HttpServletResponse response, int days) { Date expiresDate = DateUtils.addDays(new Date(), days); setExpires(response, expiresDate); } private  CacheHeader(); static boolean isNotModified(@NotNull Resource resource,
      @NotNull SlingHttpServletRequest request, @NotNull SlingHttpServletResponse response); static boolean isNotModified(@NotNull Resource resource,
      @NotNull SlingHttpServletRequest request, @NotNull SlingHttpServletResponse response, boolean setExpiresHeader); static boolean isNotModified(@NotNull ModificationDateProvider dateProvider,
      @NotNull SlingHttpServletRequest request, @NotNull SlingHttpServletResponse response); static boolean isNotModified(@NotNull ModificationDateProvider dateProvider,
      @NotNull SlingHttpServletRequest request, @NotNull SlingHttpServletResponse response, boolean setExpiresHeader); static void setNonCachingHeaders(@NotNull HttpServletResponse response); static void setExpires(@NotNull HttpServletResponse response, @Nullable Date date); static void setExpiresSeconds(@NotNull HttpServletResponse response, int seconds); static void setExpiresHours(@NotNull HttpServletResponse response, int hours); static void setExpiresDays(@NotNull HttpServletResponse response, int days);  }
@Test void testSetExpiresDays() { doAnswer(new ValidateDateHeaderAnswer(20 * DateUtils.MILLIS_PER_DAY)) .when(response).setHeader(eq(CacheHeader.HEADER_EXPIRES), anyString()); CacheHeader.setExpiresDays(response, 20); }