var test = require('../util/test')(__filename);

var variance = require('../../packages/array-variance');

test('array of numbers returns variance value', function(t) {

t.plan(4);

t.equal(variance([1, 2, 3, 2, 4, 1]).toFixed(4), '1.3667');

t.equal(variance([3, 2.5, 1]).toFixed(4), '1.0833');

t.equal(variance([1, 2, 3, 4, 5, 6]), 3.5);

t.equal(variance([1, 2, 3, 4, 5, -6]), 15.5);

t.end();

});

test('list of numeric arguments variance value', function(t) {

t.plan(4);

t.equal(variance(1, 8, 6), 13);

t.equal(variance(100, 100, 100.1, 100).toFixed(4), '0.0025');

t.equal(variance(-1, -2), 0.5);

t.equal(variance(0.1, 0.2, 0.3).toFixed(2), '0.01');

t.end();

});

test('one or fewer values throw', function(t) {

t.plan(4);

t.throws(function() {

variance([1]);

});

t.throws(function() {

variance(17.1);

});

t.throws(function() {

variance();

});

t.throws(function() {

variance([]);

});

t.end();

});

test('non-numeric values throw', function(t) {

t.plan(4);

t.throws(function() {

variance(['1', '2', '3']);

});

t.throws(function() {

variance(['a', 'b', 'c']);

});

t.throws(function() {

variance(undefined);

});

t.throws(function() {

variance([NaN, NaN]);

});

t.end();

});