@Test
    public void testPPTXThumbnail() throws Exception {
        String xml = getXML("testPPTX_Thumbnail.pptx", parseContext).xml;
        int a = xml.indexOf(
                "<body><div class=\"slide-content\"><p>This file contains an embedded thumbnail");
        int b = xml.indexOf("<div class=\"embedded\" id=\"/docProps/thumbnail.jpeg\" />");
        assertTrue(a != -1);
        assertTrue(b != -1);
        assertTrue(a < b);
    }
TIKA-712 Master Slide Text from PPT and PPTX files
should be extracted too
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/test/java/org/apache/tika/parser/microsoft/ooxml/SXSLFExtractorTest.java