--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/layout/hierarchy-test.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,30 @@
+require("../env");
+require("../../d3");
+require("../../d3.layout");
+
+var vows = require("vows"),
+    assert = require("assert");
+
+var suite = vows.describe("d3.layout.hierarchy");
+
+suite.addBatch({
+  "hierarchy": {
+    topic: function() {
+      return d3.layout.treemap(); // hierarchy is abstract, so test a subclass
+    },
+    "doesn't overwrite the value of a node that has an empty children array": function(hierarchy) {
+      var nodes = hierarchy.sticky(true).nodes({value: 1, children: []});
+      assert.equal(nodes[0].value, 1);
+      hierarchy.nodes(nodes[0]);
+      assert.equal(nodes[0].value, 1);
+    },
+    "a valueless node that has an empty children array gets a value of 0": function(hierarchy) {
+      var nodes = hierarchy.sticky(true).nodes({children: []});
+      assert.equal(nodes[0].value, 0);
+      hierarchy.nodes(nodes[0]);
+      assert.equal(nodes[0].value, 0);
+    }
+  }
+});
+
+suite.export(module);