diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/test/core/selection-on-test.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/core/selection-on-test.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,95 @@
+require("../env");
+require("../../d3");
+
+var vows = require("vows"),
+    assert = require("assert");
+
+var suite = vows.describe("selection.on");
+
+suite.addBatch({
+  "select(body)": {
+    topic: function() {
+      return d3.select("body").html("");
+    },
+    "registers an event listener for the specified type": function(body) {
+      var form = body.append("form"), count = 0;
+      form.on("submit", function() { ++count; }); // jsdom has spotty event support
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(count, 1);
+    },
+    "replaces an existing event listener for the same type": function(body) {
+      var form = body.append("form"), count = 0, fail = 0;
+      form.on("submit", function() { ++fail; });
+      form.on("submit", function() { ++count; });
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(count, 1);
+      assert.equal(fail, 0);
+    },
+    "removes an existing event listener": function(body) {
+      var form = body.append("form"), fail = 0;
+      form.on("submit", function() { ++fail; });
+      form.on("submit", null);
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(fail, 0);
+    },
+    "ignores removal of non-matching event listener": function(body) {
+      body.append("form").on("submit", null);
+    },
+    "observes the specified namespace": function(body) {
+      var form = body.append("form"), foo = 0, bar = 0;
+      form.on("submit.foo", function() { ++foo; });
+      form.on("submit.bar", function() { ++bar; });
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(foo, 1);
+      assert.equal(bar, 1);
+    },
+    /*
+    Not really sure how to test this one…
+    "observes the specified capture flag": function(body) {
+    },
+    */
+    "passes the current data and index to the event listener": function(body) {
+      var forms = body.html("").selectAll("form").data(["a", "b"]).enter().append("form"), dd, ii, data = new Object();
+      forms.on("submit", function(d, i) { dd = d; ii = i; });
+      forms.append("input").attr("type", "submit")[0][1].click();
+      assert.equal(dd, "b");
+      assert.equal(ii, 1);
+      forms[0][1].__data__ = data;
+      forms.append("input").attr("type", "submit")[0][1].click();
+      assert.equal(dd, data);
+      assert.equal(ii, 1);
+    },
+    "uses the current element as the context": function(body) {
+      var forms = body.html("").selectAll("form").data(["a", "b"]).enter().append("form"), context;
+      forms.on("submit", function() { context = this; });
+      forms.append("input").attr("type", "submit")[0][1].click();
+      assert.domEqual(context, forms[0][1]);
+    },
+    "sets the current event as d3.event": function(body) {
+      var form = body.append("form"), event;
+      form.on("submit", function() { event = d3.event; });
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(event.type, "submit");
+      assert.domEqual(event.target, form[0][0]);
+    },
+    "restores the original event after notifying listeners": function(body) {
+      var form = body.append("form"), event = d3.event = new Object();
+      form.on("submit", function() {});
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(d3.event, event);
+    },
+    "returns the current selection": function(body) {
+      assert.isTrue(body.on("submit", function() {}) === body);
+    },
+    "returns the assigned listener if called with one argument": function(body) {
+      body.on("mouseover", f).on("click.foo", f);
+      function f() {}
+      assert.equal(body.on("mouseover"), f);
+      assert.equal(body.on("click.foo"), f);
+      assert.isUndefined(body.on("click"));
+      assert.isUndefined(body.on("mouseover.foo"));
+    }
+  }
+});
+
+suite.export(module);