@Test
public void openDocumentTwice_fileSource() throws TaskIOException, IOException {

    PdfFileSource source = BaseTaskTest.customInputAsFileSource("pdf/test_file.pdf");
    try(PDDocumentHandler handler = new DefaultPdfSourceOpener().open(source)) {
        assertNotNull(handler.getUnderlyingPDDocument());
    }
    try(PDDocumentHandler handler = new DefaultPdfSourceOpener().open(source)) {
        assertNotNull(handler.getUnderlyingPDDocument());
    }
}