var vows = require(“vows”),

load = require("../load"),
assert = require("../assert");

var suite = vows.describe(“d3.descending”);

suite.addBatch({

"descending": {
  topic: load("arrays/descending").expression("d3.descending"),
  "numbers": {
    "returns a negative number if a > b": function(descending) {
      assert.isTrue(descending(1, 0) < 0);
    },
    "returns a positive number if a < b": function(descending) {
      assert.isTrue(descending(0, 1) > 0);
    },
    "returns zero if a == b": function(descending) {
      assert.equal(descending(0, 0), 0);
    },
    "returns NaN if a or b is undefined": function(descending) {
      assert.isNaN(descending(0, undefined));
      assert.isNaN(descending(undefined, 0));
      assert.isNaN(descending(undefined, undefined));
    },
    "returns NaN if a or b is NaN": function(descending) {
      assert.isNaN(descending(0, NaN));
      assert.isNaN(descending(NaN, 0));
      assert.isNaN(descending(NaN, NaN));
    }
  },
  "strings": {
    "returns a negative number if a > b": function(descending) {
      assert.isTrue(descending("b", "a") < 0);
    },
    "returns a positive number if a < b": function(descending) {
      assert.isTrue(descending("a", "b") > 0);
    },
    "returns zero if a == b": function(descending) {
      assert.equal(descending("a", "a"), 0);
    }
  }
}

});

suite.export(module);