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

var once = require('../../packages/function-once');

test('requires a function as first argument', function(t) {

t.plan(3);

t.throws(function() {

once(undefined);

});

t.throws(function() {

once({});

});

t.equal(typeof once(function() {}), 'function');

});

test('runs only once', function(t) {

t.plan(2);

var callCounter = 0;

var fn = once(function() {

callCounter++;

});

fn();

t.equal(callCounter, 1);

fn();

t.equal(callCounter, 1);

});

test('forwards arguments', function(t) {

t.plan(2);

var callCounter = 0;

var fn = once(function(delta) {

callCounter += delta;

});

fn(2);

t.equal(callCounter, 2);

fn(3);

t.equal(callCounter, 2);

});

test('forwards context', function(t) {

t.plan(2);

var callCounter = 0;

var fn = once(function(delta) {

callCounter += this;

});

fn.call(2);

t.equal(callCounter, 2);

fn.call(3);

t.equal(callCounter, 2);

});