var assert = require(“../assert”),

_ = require("../../");

var datum = {};

module.exports = {

topic: function(d3) {
  return d3.select("body").html("").selectAll("div")
      .data([0, 1])
    .enter().append("div")
    .selectAll("span")
      .data(function(d) { d <<= 1; return [d, d + 1]; })
    .enter().append("span")
      .classed("foo", function(d, i) { return d & 1; })
    .transition()
      .delay(100)
      .duration(150)
      .ease("bounce");
},

"preserves matching elements": function(span) {
  var some = span.filter(function(d, i) { return i === 0; });
  assert.isTrue(some[0][0] === span[0][0]);
  assert.isTrue(some[1][0] === span[1][0]);
},
"removes non-matching elements": function(span) {
  var some = _.merge(span.filter(function(d, i) { return d & 1; }));
  assert.equal(some.indexOf(span[0][0]), -1);
  assert.equal(some.indexOf(span[1][0]), -1);
},
"preserves data": function(span) {
  var some = span.filter(function(d, i) { return d & 1; });
  assert.equal(some[0][0].__data__, 1);
  assert.equal(some[1][0].__data__, 3);
},
"preserves grouping": function(span) {
  var some = span.filter(function(d, i) { return d & 1; });
  assert.equal(some.length, 2);
  assert.equal(some[0].length, 1);
  assert.equal(some[1].length, 1);
},
"preserves parent node": function(span) {
  var some = span.filter(function(d, i) { return d & 1; });
  assert.isTrue(some[0].parentNode === span[0].parentNode);
  assert.isTrue(some[1].parentNode === span[1].parentNode);
},
"does not preserve index": function(span) {
  var indexes = [];
  span.filter(function(d, i) { return d & 1; }).each(function(d, i) { indexes.push(i); });
  assert.deepEqual(indexes, [0, 0]);
},
"ignores null nodes": function(span) {
  var node = span[0][1];
  span[0][1] = null;
  var some = span.filter(function(d, i) { return d & 1; });
  assert.isTrue(some[0][0] === span[0][3]);
  assert.equal(some.length, 2);
  span[0][1] = node;
},
"can be specified as a selector": function(span) {
  var some = span.filter(".foo");
  assert.equal(some.length, 2);
  assert.equal(some[0].length, 1);
  assert.equal(some[1].length, 1);
},
"returns a new selection": function(span) {
  assert.isFalse(span.filter(function() { return 1; }) === span);
},
"inherits the delay": function(t1) {
  var t2 = t1.filter(function() { return 1; });
  assert.equal(t2[0][0].__transition__[t2.id].delay, 100); // TODO should inherit the whole transition object
},
"inherits the duration": function(t1) {
  var t2 = t1.filter(function() { return 1; });
  assert.equal(t2[0][0].__transition__[t2.id].duration, 150);
},
"inherits easing": function(t1) {
  // TODO how to test this?
},
"inherits the transition id": function(t1) {
  var t2 = t1.filter(function() { return 1; });
  assert.equal(t2.id, t1.id);
}

};