Write full test coverage for the Discover card

// Write full test coverage for the Discover card
describe('Discover', function() {
  // Tests without a function will be marked as "pending" and not run
  // Implement these tests (and others) and make them pass!
  it('has a prefix of 6011 and a length of 16', function() {
    detectNetwork('6011345678901234').should.equal('Discover');
  });
  it('has a prefix of 6011 and a length of 19', function() {
    detectNetwork('6011345678901234012').should.equal('Discover');
  });

  // When it has a prefix of 65
  it('has a prefix of 65 and a length of 16', function() {
    detectNetwork('6521345678901234').should.equal('Discover');
  });
  it('has a prefix of 65 and a length of 19', function() {
    detectNetwork('6576011345678901234').should.equal('Discover');
  });

  for (var prefix = 644; prefix <= 649; prefix++) {
    (function(currentPrefix) {
      it('has a prefix of ' + currentPrefix + ' and a length of 16', function() {
        detectNetwork(currentPrefix + '1345678901234').should.equal('Discover');
      });
    })(prefix);
  }

  for (var prefix = 644; prefix <= 649; prefix++) {
    (function(currentPrefix) {
      it('has a prefix of ' + currentPrefix + ' and a length of 19', function() {
        detectNetwork(currentPrefix + '6011345678901234').should.equal('Discover');
      });
    })(prefix);
  }
});