diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/test/core/formatPrefix-test.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/test/core/formatPrefix-test.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,108 @@
+require("../env");
+require("../../d3");
+
+var vows = require("vows"),
+    assert = require("assert");
+
+var suite = vows.describe("d3.formatPrefix");
+
+suite.addBatch({
+  "formatPrefix": {
+    topic: function() {
+      return d3.formatPrefix;
+    },
+    "determines the appropriate prefix for small numbers": function(prefix) {
+      assert.equal(prefix(0).symbol, "");
+      assert.equal(prefix(1e-00).symbol, "");
+      assert.equal(prefix(1e-01).symbol, "");
+      assert.equal(prefix(1e-02).symbol, "");
+      assert.equal(prefix(1e-03).symbol, "m");
+      assert.equal(prefix(1e-04).symbol, "m");
+      assert.equal(prefix(1e-05).symbol, "m");
+      assert.equal(prefix(1e-06).symbol, "μ");
+      assert.equal(prefix(1e-07).symbol, "μ");
+      assert.equal(prefix(1e-08).symbol, "μ");
+      assert.equal(prefix(1e-09).symbol, "n");
+      assert.equal(prefix(1e-10).symbol, "n");
+      assert.equal(prefix(1e-11).symbol, "n");
+      assert.equal(prefix(1e-12).symbol, "p");
+      assert.equal(prefix(1e-13).symbol, "p");
+      assert.equal(prefix(1e-14).symbol, "p");
+      assert.equal(prefix(1e-15).symbol, "f");
+      assert.equal(prefix(1e-16).symbol, "f");
+      assert.equal(prefix(1e-17).symbol, "f");
+      assert.equal(prefix(1e-18).symbol, "a");
+      assert.equal(prefix(1e-19).symbol, "a");
+      assert.equal(prefix(1e-20).symbol, "a");
+      assert.equal(prefix(1e-21).symbol, "z");
+      assert.equal(prefix(1e-22).symbol, "z");
+      assert.equal(prefix(1e-23).symbol, "z");
+      assert.equal(prefix(1e-24).symbol, "y");
+      assert.equal(prefix(1e-25).symbol, "y");
+      assert.equal(prefix(1e-26).symbol, "y");
+      assert.equal(prefix(1e-27).symbol, "y");
+    },
+    "determines the appropriate prefix for large numbers": function(prefix) {
+      assert.equal(prefix(0).symbol, "");
+      assert.equal(prefix(1e00).symbol, "");
+      assert.equal(prefix(1e01).symbol, "");
+      assert.equal(prefix(1e02).symbol, "");
+      assert.equal(prefix(1e03).symbol, "k");
+      assert.equal(prefix(1e04).symbol, "k");
+      assert.equal(prefix(1e05).symbol, "k");
+      assert.equal(prefix(1e06).symbol, "M");
+      assert.equal(prefix(1e07).symbol, "M");
+      assert.equal(prefix(1e08).symbol, "M");
+      assert.equal(prefix(1e09).symbol, "G");
+      assert.equal(prefix(1e10).symbol, "G");
+      assert.equal(prefix(1e11).symbol, "G");
+      assert.equal(prefix(1e12).symbol, "T");
+      assert.equal(prefix(1e13).symbol, "T");
+      assert.equal(prefix(1e14).symbol, "T");
+      assert.equal(prefix(1e15).symbol, "P");
+      assert.equal(prefix(1e16).symbol, "P");
+      assert.equal(prefix(1e17).symbol, "P");
+      assert.equal(prefix(1e18).symbol, "E");
+      assert.equal(prefix(1e19).symbol, "E");
+      assert.equal(prefix(1e20).symbol, "E");
+      assert.equal(prefix(1e21).symbol, "Z");
+      assert.equal(prefix(1e22).symbol, "Z");
+      assert.equal(prefix(1e23).symbol, "Z");
+      assert.equal(prefix(1e24).symbol, "Y");
+      assert.equal(prefix(1e25).symbol, "Y");
+      assert.equal(prefix(1e26).symbol, "Y");
+      assert.equal(prefix(1e27).symbol, "Y");
+    },
+    "determines the appropriate prefix for negative numbers": function(prefix) {
+      assert.equal(prefix(-0).symbol, "");
+      assert.equal(prefix(-1e-00).symbol, "");
+      assert.equal(prefix(-1e-03).symbol, "m");
+      assert.equal(prefix(-1e-06).symbol, "μ");
+      assert.equal(prefix(-1e-09).symbol, "n");
+      assert.equal(prefix(-1e-12).symbol, "p");
+      assert.equal(prefix(-1e-15).symbol, "f");
+      assert.equal(prefix(-1e-18).symbol, "a");
+      assert.equal(prefix(-1e-21).symbol, "z");
+      assert.equal(prefix(-1e-24).symbol, "y");
+      assert.equal(prefix(-1e-27).symbol, "y");
+      assert.equal(prefix(-1e00).symbol, "");
+      assert.equal(prefix(-1e03).symbol, "k");
+      assert.equal(prefix(-1e06).symbol, "M");
+      assert.equal(prefix(-1e09).symbol, "G");
+      assert.equal(prefix(-1e12).symbol, "T");
+      assert.equal(prefix(-1e15).symbol, "P");
+      assert.equal(prefix(-1e18).symbol, "E");
+      assert.equal(prefix(-1e21).symbol, "Z");
+      assert.equal(prefix(-1e24).symbol, "Y");
+      assert.equal(prefix(-1e27).symbol, "Y");
+    },
+    "considers the effect of rounding based on precision": function(prefix) {
+      assert.equal(prefix(999.5, 3).symbol, "k");
+      assert.equal(prefix(999.5, 4).symbol, "");
+      assert.equal(prefix(.009995, 3).symbol, "");
+      assert.equal(prefix(.009995, 4).symbol, "m");
+    }
+  }
+});
+
+suite.export(module);