@Test
  public void testNumbersToWords() {
    assertEquals("Give me a high five", ntn.numbersToWords("Give me a high 5"));
    assertEquals("I'm sixteen years old.", ntn.numbersToWords("I'm 16 years old."));
    assertEquals("seven hundred thirteenpeople died.", ntn.numbersToWords("713people died."));
    assertEquals(
        "987737/eighty eight !=one thousand one hundred twenty two",
        ntn.numbersToWords("987737/88 !=1122"));

    assertEquals(
        "Today is two thousand eleven November eleventh.",
        ntn.numbersToWords("Today is 2011 November 11th."));
    assertEquals(
        "Avogadro's Constant = six.two thousand two hundred fourteen x ten ^ twenty three mol -one",
        ntn.numbersToWords("Avogadro's Constant = 6.02214 x 10 ^ 23 mol -1"));

    // more
    assertEquals("Pi is roughly three.14159", ntn.numbersToWords("Pi is roughly 3.14159"));
    assertEquals("nine.ninety nine", ntn.numbersToWords("9.99"));

    // preceding zeros
    assertEquals("one hundred one", ntn.numbersToWords("0101"));
    assertEquals("one hundred eleven", ntn.numbersToWords("0111"));

    assertEquals("twenty three", ntn.numbersToWords("0023"));
    assertEquals("twenty three", ntn.numbersToWords("023"));

    assertEquals("ten", ntn.numbersToWords("0010"));
    assertEquals("ten", ntn.numbersToWords("010"));

    assertEquals("fifteen", ntn.numbersToWords("0015"));
    assertEquals("fifteen", ntn.numbersToWords("015"));

    assertEquals("one", ntn.numbersToWords("0001"));
    assertEquals("one", ntn.numbersToWords("001"));
    assertEquals("one", ntn.numbersToWords("01"));

    assertEquals("zero", ntn.numbersToWords("0000"));
    assertEquals("zero", ntn.numbersToWords("000"));
    assertEquals("zero", ntn.numbersToWords("00"));

    // TODO delete these lines
    assertEquals("Hello world!", ntn.numbersToWords("Hello world!"));
    assertEquals("Heone hundred ten wzeroroned!", ntn.numbersToWords("He110 w0r1d!"));
    assertEquals("The time is now three:fifteen.", ntn.numbersToWords("The time is now 3:15."));
    assertEquals(
        "Pai = three.one thousand four hundred fifteen", ntn.numbersToWords("Pai = 3.1415"));
    assertEquals(
        "Tninehe quninety eightick brotwenty eightwn fthree hundred seventy eightox jueight hundred seventy sixmps oone thousandver the lathirty threezy doneotwog.",
        ntn.numbersToWords("T9he qu98ick bro28wn f378ox ju876mps o1000ver the la33zy d1o2g."));
    assertEquals("nine thousand nine hundred ninety nine", ntn.numbersToWords("009999"));
    assertEquals("This is a 10000.", ntn.numbersToWords("This is a 10000."));
  }