  @Test
  private void testCoordinates() {

    String pdfPath = "/coordinate_calibrator.pdf";
    InputStream pdfInputStream = getClass().getResourceAsStream(pdfPath);
    PDFExtractor.Options opts = PDFExtractor.Options.builder().useHeuristicTitle(true).build();
    PDFDoc doc = new PDFExtractor(opts).extractFromInputStream(pdfInputStream);
    
    for(PDFPage p : doc.pages) {
      for(PDFLine l : p.lines) {
        for(PDFToken t : l.tokens) {
          Assert.assertEquals(t.token, "M"); //should be in upper-left:
          System.out.println("bounds x0: " + t.bounds.get(0) + " y0: " + t.bounds.get(1));
          Assert.assertTrue(t.bounds.get(0) < 0.1);
          Assert.assertTrue(t.bounds.get(1) < 0.1);
        }
      }
    }
  }