### Question:
VideoRecordingFileName { public String getFileName(String prefix, String suffix) { String fileName = IrisString.joinIfNotEmpty("_", prefix, suffix); if (StringUtils.isEmpty(fileName)) return ""; return String.format("%s.mp4", fileName); } VideoRecordingFileName(
         UUID recordingId,
         UUID cameraId,
         UUID placeId,
         DeviceDAO deviceDAO,
         PlaceDAO placeDAO
         ); String getByDeviceOrDefault(); String getByDevice(); String getFileName(String prefix, String suffix); String getDateSuffix(Place place); String localDateSuffix(Place place, Date date);  }### Answer:
@Test public void getFileName() { VideoRecordingFileName sut = new VideoRecordingFileName( UUID.randomUUID(), UUID.randomUUID(), UUID.randomUUID(), createNiceMock(DeviceDAO.class), createNiceMock(PlaceDAO.class)); String result = sut.getFileName("prefix", "suffix"); Assert.assertEquals("prefix_suffix.mp4", result); }