module.exports = function Dynamic(options, UI, util) {
  // Tests for functions that are available inside modules only

  var output;

  // This function is called on every draw.
  function draw(input, callback) {

    var step = this;

    if (this.getPreviousStep().options.name != "invert") throw new Error("getPreviousStep not working");
    if (this.getNextStep().options.name != "invert") throw new Error("getNextStep not working");
    if (this.getInput(0) != this.getOutput(-1)) throw new Error("getInput and getOuput now working")
    if (this.getFormat() != "jpeg") throw new Error("getFormat not working");
    if (this.getOptions().name != "test") throw new Error("getOptions not working");
    this.setOptions({ name: "test-1" });
    if (this.getOptions().name != "test-1") throw new Error("setOptions not working not working");
    this.getHeight(((h) => { if (h != 16) throw new Error("getHeight not working") }));
    this.getWidth((w) => { if (w != 16) throw new Error("getWidth not working") });

    function output(image, datauri, mimetype) {
      step.output = input;
    }

  }

  return {
    options: options,
    draw: draw,
    output: output,
    UI: UI
  }
}