diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/test/core/transition-test-attr.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/core/transition-test-attr.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,54 @@
+require("../env");
+require("../../d3");
+
+var assert = require("assert");
+
+module.exports = {
+  topic: function() {
+    var cb = this.callback;
+
+    var s = d3.select("body").append("div")
+        .attr("display", "none")
+        .attr("font-size", "20px")
+        .attr("width", 20)
+        .attr("color", "red")
+        .attr("xlink:type", "simple")
+        .attr("xlink:href", "http://mbostock.github.com/d3/");
+
+    var t = s.transition()
+        .attr("display", null)
+        .attr("font-size", function() { return null; })
+        .attr("display", null)
+        .attr("width", 100)
+        .attr("width", 200)
+        .attr("color", function() { return "green"; })
+        .attr("xlink:href", null)
+        .attr("xlink:type", function() { return null; })
+        .each("end", function() { cb(null, {selection: s, transition: t}); });
+  },
+  "defines the corresponding attr tween": function(result) {
+    assert.typeOf(result.transition.tween("attr.width"), "function");
+    assert.typeOf(result.transition.tween("attr.color"), "function");
+  },
+  "the last attr operator takes precedence": function(result) {
+    assert.equal(result.selection.attr("width"), "200");
+  },
+  "sets an attribute as a number": function(result) {
+    assert.equal(result.selection.attr("width"), "200");
+  },
+  "sets an attribute as a function": function(result) {
+    assert.equal(result.selection.attr("color"), "#008000");
+  },
+  "removes an attribute using a constant null": function(result) {
+    assert.equal(result.selection.attr("display"), "");
+  },
+  "removes an attribute using a function null": function(result) {
+    assert.equal(result.selection.attr("font-size"), "");
+  },
+  "removes a namespaced attribute using a constant null": function(result) {
+    assert.equal(result.selection.attr("xlink:href"), "");
+  },
+  "removes a namespaced attribute using a function null": function(result) {
+    assert.equal(result.selection.attr("xlink:type"), "");
+  }
+};