@Test
    public void testGetExtensionForPowerPoint() throws Exception {
        MimeType mt = this.mimeTypes.forName("application/vnd.ms-powerpoint");
        String ext = mt.getExtension();
        assertEquals(".ppt", ext);
        assertEquals(".ppt", mt.getExtensions().get(0));
    }
TIKA-2460 Test loading of custom-mimetypes.xml from sys prop.
tika-core/src/test/java/org/apache/tika/mime/MimeTypesReaderTest.java