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);