code: @Test public void testThatFlashCookieWorksAndIsActiveOnlyOneTime(){
    Cookie cookie=Cookie.builder("NINJA_FLASH","hello=flashScope").build();
    when(context.getCookie("NINJA_FLASH")).thenReturn(cookie);
    FlashCookie flashCookie=new FlashCookieImpl(ninjaProperties);
    flashCookie.init(context);
    assertEquals("flashScope",flashCookie.get("hello"));
    flashCookie.put("another message","is there...");
    flashCookie.put("yet another message","is there...");
    flashCookie.save(context,result);
    verify(result).addCookie(cookieCaptor.capture());
    assertEquals("NINJA_FLASH",cookieCaptor.getValue().getName());
    assertEquals("another+message=is+there...&yet+another+message=is+there...",cookieCaptor.getValue().getValue());
    assertEquals(3,((FlashCookieImpl)flashCookie).getCurrentFlashCookieData().size());
    assertEquals(2,((FlashCookieImpl)flashCookie).getOutgoingFlashCookieData().size());
  }
  