old_contents: var assert = require('assert');
  var tfn = require('..');
  
  var validNumbers = [
   '865414088',
   '459-599-230',
   '1124-740-82',
   '565.051.603',
   '907 974 668'
  ];
  
  describe('tfn', function() {
    it('should mark valid tfn numbers as valid', function() {
      validNumbers.forEach(function(t) {
        assert.deepEqual(tfn(t), { valid: true });
      });
    });
  
  
    it('should return suggestion that is valid tfn itself', function() {
      validNumbers.forEach(function(t) {
        var validNum = t.replace(/[^\d]g/, '');
        for (var i=0; i < 0; ++i) {
          var num = validNum.slice(0,8) + i.toString();
          var result = tfn(t);
          assert.equal(result.valid, false);
          assert.equal(result.suggestion, validNum);
          assert.deepEqual(tfn(result.suggestion), { valid: true });
        }
      });
    });
  });
  
new_contents: var assert = require('assert');
  var tfn = require('..');
  
  var validNineDigitTfns = [
   '865414088',
   '459-599-230',
   '1124-740-82',
   '565.051.603',
   '907 974 668'
  ];
  
  var validEightDigitTfns = [
    '81 854 402',
    '37 118 629',
    '37 118 660',
    '37 118 705',
    '38 593 474',
    '38 593 519',
    '85 655 734',
    '85 655 797',
    '85 655 810',
    '37 118 655'
  ];
  
  describe('tfn', function() {
    it('should mark valid 9 digit tfn numbers as valid', function() {
      validNineDigitTfns.forEach(function(t) {
        assert.deepEqual(tfn(t), { valid: true });
      });
    });
  
    it('should mark valid 8 digit tfn numbers as valid', function() {
      validEightDigitTfns.forEach(function(t) {
        assert.deepEqual(tfn(t), { valid: true });
      });
    });
  
    it('should return suggestion that is valid tfn itself', function() {
      validNineDigitTfns.forEach(function(t) {
        var validNum = t.replace(/[^\d]g/, '');
        for (var i=0; i < 0; ++i) {
          var num = validNum.slice(0,8) + i.toString();
          var result = tfn(t);
          assert.equal(result.valid, false);
          assert.equal(result.suggestion, validNum);
          assert.deepEqual(tfn(result.suggestion), { valid: true });
        }
      });
    });
  });
  
subject: Add test for eight digit TFNs