private Jinjava templateRender = new Jinjava();


 @PostMapping("/reverseString")
@ResponseBody
public String inverseString(@RequestParam("text") String text,
                            @RequestParam(value = "tailRecurse", defaultValue = "false") Boolean useTaleRecurse)
{
    Map<String, Object> map = Maps.newHashMap();
    if (useTaleRecurse)
        map.put("detail", reverseString("", text, text.length()));
    else
        map.put("detail", new StringBuffer(text).reverse().toString());
    return templateRender.render(getTemplate("index.html"), map);
}



 private String reverseString(String accumulator,String source, int size)
{
    if (size == 0)
        return accumulator;
    return reverseString(accumulator.concat(source.substring(size - 1, size)), source, size - 1);
}

...
@Test
public void getPersons() throws Exception {
    this.mockMvc.perform(post("/reverseString?text=SStringS&tailRecurse=true"))
      .andExpect(status().isOk());
}
...