require("../env");

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

var vows = require("vows"),

assert = require("assert");

var suite = vows.describe("d3.quantile");

suite.addBatch({

"quantile": {

topic: function() {

return d3.quantile;

},

"requires sorted numeric input": function(quantile) {

assert.equal(quantile([1, 2, 3, 4], 0), 1);

assert.equal(quantile([1, 2, 3, 4], 1), 4);

assert.equal(quantile([4, 3, 2, 1], 0), 4);

assert.equal(quantile([4, 3, 2, 1], 1), 1);

},

"uses the R-7 algorithm": function(quantile) {

var data = [3, 6, 7, 8, 8, 10, 13, 15, 16, 20];

assert.equal(quantile(data, 0), 3);

assert.equal(quantile(data, .25), 7.25);

assert.equal(quantile(data, .5), 9);

assert.equal(quantile(data, .75), 14.5);

assert.equal(quantile(data, 1), 20);

var data = [3, 6, 7, 8, 8, 9, 10, 13, 15, 16, 20];

assert.equal(quantile(data, 0), 3);

assert.equal(quantile(data, .25), 7.5);

assert.equal(quantile(data, .5), 9);

assert.equal(quantile(data, .75), 14);

assert.equal(quantile(data, 1), 20);

},

"returns an exact value for integer p-values": function(quantile) {

var a = {}, b = {}, c = {}, d = {}, data = [a, b, c, d];

assert.equal(quantile(data, 1/3), b);

assert.equal(quantile(data, 2/3), c);

},

"returns the first value for p = 0": function(quantile) {

var a = {}, b = {}, c = {}, d = {}, data = [a, b, c, d];

assert.equal(quantile(data, 0), a);

},

"returns the last value for p = 1": function(quantile) {

var a = {}, b = {}, c = {}, d = {}, data = [a, b, c, d];

assert.equal(quantile(data, 1), d);

}

}

});

suite.export(module);