private static ComparisonFailureData createFileComparisonData(Throwable assertion) {
    if (assertion instanceof FileComparisonData) {
      final FileComparisonData comparisonFailure = (FileComparisonData)assertion;
      String actual = comparisonFailure.getActualStringPresentation();
      String expected = comparisonFailure.getExpectedStringPresentation();
      if (actual != null && expected != null) {
        return new ComparisonFailureData(expected, actual, comparisonFailure.getFilePath(), comparisonFailure.getActualFilePath());
      }
    }
    return null;
  }
private static ComparisonFailureData createFileComparisonData(Throwable assertion)