rafa/test/unit/core/Stream-enumerate.js

Rafa.js is a Javascript framework for building concurrent applications.

module.exports = (assert, Rafa) => {
  suite("enumerate", () => {
    test("sync enumerate array", () => {
      var it = Rafa.Enumerator.array([1,2]);
      var stream = Rafa.stream();
      var values = [];
      stream.each(v => values.push(v));
      stream.done(v => values.push(v));
      stream.enumerate(it);
      assert.equal(values.length, 3);
      assert.equal(values[0], 1);
      assert.equal(values[1], 2);
      assert.equal(values[2], 2);
    });

    test("async enumerate array", done => {
      var it = Rafa.Enumerator.array([1,2]);
      var stream = Rafa.stream();
      var values = [];

      stream
        .map(v => Promise.resolve(v + 1))
        .each(v => values.push(v))
        .done(v => values.push(v));

      stream.enumerate(it);

      setTimeout(() => {
        assert.equal(values.length, 3);
        assert.equal(values[0], 2);
        assert.equal(values[1], 3);
        assert.equal(values[2], 3);
        done();
      });
    });

    test("channel", () => {
      var channel = Rafa.channel();
      var stream = Rafa.stream();
      var values = [];
      stream.enumerate(channel).each(v => values.push(v));
      channel.write(1);
      assert.equal(values.length, 1);
      assert.equal(values[0], 1);
    });

    test("channel backpressure", () => {
      var channel = Rafa.channel();
      var stream = Rafa.stream();
      var nested;
      var values = [];
      var child = stream.enumerate(channel).flatMap(v => {
        values.push(v);
        return nested = Rafa.stream();
      });
      child.each(v => values.push(v));

      // writing once should flow through the flatMap
      channel.write(1);
      assert.equal(values.length, 1);
      assert.equal(values[0], 1);

      // writing again should drop the write since flatMap hasn't fired
      assert.equal(channel.write(2), 0);
      assert.equal(values.length, 1);

      // write done message from the flatMap nested stream 
      // clears the channel for more writes
      nested.write(3, true);
      assert.equal(values.length, 2);
      assert.equal(values[1], 3);
      channel.write(4);
      assert.equal(values.length, 3);
      assert.equal(values[2], 4);
    });
  });
};