source: class SacLoaderTest {
  
      private SacLoader loader;
  
      @Test
      public void testEventDepthPopulated() throws Exception {
  
target:         //GMPAPPS-1947 Envelope tool was dropping event depth info.
          List<List<File>> multipleFiles = IntStream.range(0, 3).mapToObj(i -> {
              try (Stream<Path> stream = Files.walk(Paths.get("src/test/resources/sac/"))) {
                  return stream.filter(path -> path.getFileName().toString().toLowerCase(Locale.ENGLISH).endsWith(".sac")).map(path -> path.toFile()).collect(Collectors.toList());
              } catch (IOException e) {
                  e.printStackTrace();
                  return null;
              }
          }).filter(o -> o != null).collect(Collectors.toList());
          List<Result<Waveform>> results = loader.convertFiles(multipleFiles.get(0)).doOnError(error -> Assertions.fail(error.getMessage())).collectList().block(Duration.ofSeconds(10l));
          for (Result<Waveform> res : results) {
              Assertions.assertTrue(res.getResultPayload().get().getEvent().getDepth() != 0, "Expect that the waveform should have a populated event depth if the original file had it.");
          }
      }
  
  }