diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/test/core/selection-test.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/core/selection-test.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,35 @@
+require("../env");
+require("../../d3");
+
+var vows = require("vows"),
+    assert = require("assert");
+
+var suite = vows.describe("d3.selection");
+
+suite.addBatch({
+  "selection": {
+    topic: function() {
+      return d3.selection();
+    },
+    "selects the document": function(selection) {
+      assert.equal(selection.length, 1);
+      assert.equal(selection[0].length, 1);
+      assert.equal(selection[0][0], document);
+    },
+    "is an instanceof d3.selection": function(selection) {
+      assert.isTrue(selection instanceof d3.selection);
+    },
+    "subselections are also instanceof d3.selection": function(selection) {
+      assert.isTrue(selection.select("body") instanceof d3.selection);
+      assert.isTrue(selection.selectAll("body") instanceof d3.selection);
+    },
+    "selection prototype can be extended": function(selection) {
+      d3.selection.prototype.foo = function(v) { return this.attr("foo", v); };
+      selection.select("body").foo(42);
+      assert.equal(document.body.getAttribute("foo"), "42");
+      delete d3.selection.prototype.foo;
+    }
+  }
+});
+
+suite.export(module);