As seen in the screenshots below , in the Debug Console you can see the actual value that candles.get(0).getOpen()
gives is the same that is asked in the assert part that is highlighted but it fails (as shown in the next image)
ps: to get this testcase running i had to modify the constructor of TiingoService to create a new instance of RestTemplate instead of assigning the one passed to it as param as nothing is passed by the test