diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/test/core/transition-test-time.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/core/transition-test-time.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,36 @@
+require("../env");
+require("../../d3");
+
+var assert = require("assert");
+
+module.exports = {
+  topic: function() {
+    return d3.select("body").append("div").transition();
+  },
+  "is approximately equal to now": function(transition) {
+    var time = transition.time;
+    assert.inDelta(time, Date.now(), 20);
+  },
+  "increases monotonically across transitions": function(transition) {
+    var now = Date.now, then = Date.now();
+    try {
+      Date.now = function() { return ++then; };
+      var t0 = d3.select("body").append("div").transition(),
+          t1 = d3.select("body").append("div").transition();
+      assert.isTrue(t1.time > t0.time);
+    } finally {
+      Date.now = now;
+    }
+  },
+  "is inherited by subtransitions": function(transition) {
+    var now = Date.now, then = Date.now();
+    try {
+      Date.now = function() { return ++then; };
+      var t0 = d3.select("body").append("div").transition(),
+          t1 = t0.transition();
+      assert.equal(t1.time, t0.time);
+    } finally {
+      Date.now = now;
+    }
+  }
+};