How can I dynamically generate test cases in javascript/node?

Yes you can dynamically created test suites with cases using Mocha. I have installed mocha globally npm install -g mocha and I use should.

var should = require('should');

var foo = 'bar';

['nl', 'fr', 'de'].forEach(function(arrElement) {
  describe(arrElement + ' suite', function() {
    it('This thing should behave like this', function(done) {
      foo.should.be.a.String();
      done();
    });
    it('That thing should behave like that', function(done) {
      foo.should.have.length(3);
      done();
    });
  });
});