### Question:
TtmlHelpers { public static String toTimeExpression(long ms) { return toTimeExpression(ms, -1); }  static void main(String[] args); static String[] getAllNamespaces(Document doc); static String toTimeExpression(long ms); static String toTimeExpression(long ms, int frames); static long toTime(String expr); static void pretty(Document document, OutputStream outputStream, int indent); static long getStartTime(Node p); static long getEndTime(Node p); static void deepCopyDocument(Document ttml, File target); static final String SMPTE_TT_NAMESPACE; static final String TTML_NAMESPACE; static final NamespaceContext NAMESPACE_CONTEXT; }### Answer:
@Test public void testToTimeExpression() throws Exception { Assert.assertEquals("-00:59:59.009", toTimeExpression(-3599009)); Assert.assertEquals("00:59:59.010", toTimeExpression(3599010)); }