1 require("../env");

     2 require("../../d3");

     3 

     4 var vows = require("vows"),

     5     assert = require("assert");

     6 

     7 var suite = vows.describe("d3.mean");

     8 

     9 suite.addBatch({

    10   "mean": {

    11     topic: function() {

    12       return d3.mean;

    13     },

    14     "returns the mean value for numbers": function(mean) {

    15       assert.equal(mean([1]), 1);

    16       assert.equal(mean([5, 1, 2, 3, 4]), 3);

    17       assert.equal(mean([20, 3]), 11.5);

    18       assert.equal(mean([3, 20]), 11.5);

    19     },

    20     "ignores null, undefined and NaN": function(mean) {

    21       assert.equal(mean([NaN, 1, 2, 3, 4, 5]), 3);

    22       assert.equal(mean([1, 2, 3, 4, 5, NaN]), 3);

    23       assert.equal(mean([10, null, 3, undefined, 5, NaN]), 6);

    24     },

    25     "can handle large numbers without overflowing": function(mean) {

    26       assert.equal(mean([Number.MAX_VALUE, Number.MAX_VALUE]), Number.MAX_VALUE);

    27       assert.equal(mean([-Number.MAX_VALUE, -Number.MAX_VALUE]), -Number.MAX_VALUE);

    28     },

    29     "returns undefined for empty array": function(mean) {

    30       assert.isUndefined(mean([]));

    31       assert.isUndefined(mean([null]));

    32       assert.isUndefined(mean([undefined]));

    33       assert.isUndefined(mean([NaN]));

    34       assert.isUndefined(mean([NaN, NaN]));

    35     },

    36     "applies the optional accessor function": function(mean) {

    37       assert.equal(d3.mean([[1, 2, 3, 4, 5], [2, 4, 6, 8, 10]], function(d) { return d3.mean(d); }), 4.5);

    38       assert.equal(d3.mean([1, 2, 3, 4, 5], function(d, i) { return i; }), 2);

    39     }

    40   }

    41 });

    42 

    43 suite.export(module);