1 require("../env");

     2 require("../../d3");

     3 

     4 var assert = require("assert");

     5 

     6 module.exports = {

     7   topic: function() {

     8     return d3.select("body").append("div").transition();

     9   },

    10   "has a positive integer id": function(transition) {

    11     var id = transition.id;

    12     assert.isTrue(id > 0);

    13     assert.equal(~~id, id);

    14   },

    15   "increases monotonically across transitions": function(transition) {

    16     var t0 = d3.select("body").append("div").transition(),

    17         t1 = d3.select("body").append("div").transition();

    18     assert.isTrue(t1.id > t0.id);

    19   }

    20 };