(function() {

  var templateSettings;

  module('Utility', {

    setup: function() {
      templateSettings = _.clone(_.templateSettings);
    },

    teardown: function() {
      _.templateSettings = templateSettings;
    }

  });

  test('#750 - Return _ instance.', 2, function() {
    var instance = _([]);
    ok(_(instance) === instance);
    ok(new _(instance) === instance);
  });

  test('identity', function() {
    var moe = {name : 'moe'};
    equal(_.identity(moe), moe, 'moe is the same as his identity');
  });

  test('constant', function() {
    var moe = {name : 'moe'};
    equal(_.constant(moe)(), moe, 'should create a function that returns moe');
  });

  test('noop', function() {
    strictEqual(_.noop('curly', 'larry', 'moe'), undefined, 'should always return undefined');
  });

  test('property', function() {
    var moe = {name : 'moe'};
    equal(_.property('name')(moe), 'moe', 'should return the property with the given name');
  });

  test('random', function() {
    var array = _.range(1000);
    var min = Math.pow(2, 31);
    var max = Math.pow(2, 62);

    ok(_.every(array, function() {
      return _.random(min, max) >= min;
    }), 'should produce a random number greater than or equal to the minimum number');

    ok(_.some(array, function() {
      return _.random(Number.MAX_VALUE) > 0;
    }), 'should produce a random number when passed `Number.MAX_VALUE`');
  });

  test('now', function() {
    var diff = _.now() - new Date().getTime();
    ok(diff <= 0 && diff > -5, 'Produces the correct time in milliseconds');//within 5ms
  });

  test('uniqueId', function() {
    var ids = [], i = 0;
    while (i++ < 100) ids.push(_.uniqueId());
    equal(_.uniq(ids).length, ids.length, 'can generate a globally-unique stream of ids');
  });

  test('times', function() {
    var vals = [];
    _.times(3, function (i) { vals.push(i); });
    deepEqual(vals, [0, 1, 2], 'is 0 indexed');
    //
    vals = [];
    _(3).times(function(i) { vals.push(i); });
    deepEqual(vals, [0, 1, 2], 'works as a wrapper');
    // collects return values
    deepEqual([0, 1, 2], _.times(3, function(i) { return i; }), 'collects return values');

    deepEqual(_.times(0, _.identity), []);
    deepEqual(_.times(-1, _.identity), []);
    deepEqual(_.times(parseFloat('-Infinity'), _.identity), []);
  });

  test('mixin', function() {
    _.mixin({
      myReverse: function(string) {
        return string.split('').reverse().join('');
      }
    });
    equal(_.myReverse('panacea'), 'aecanap', 'mixed in a function to _');
    equal(_('champ').myReverse(), 'pmahc', 'mixed in a function to the OOP wrapper');
  });

  test('_.escape', function() {
    equal(_.escape(null), '');
  });

  test('_.unescape', function() {
    var string = 'Curly & Moe';
    equal(_.unescape(null), '');
    equal(_.unescape(_.escape(string)), string);
    equal(_.unescape(string), string, 'don\'t unescape unnecessarily');
  });

  // Don't care what they escape them to just that they're escaped and can be unescaped
  test('_.escape & unescape', function() {
    // test & (&amp;) seperately obviously
    var escapeCharacters = ['<', '>', '"', '\'', '`'];

    _.each(escapeCharacters, function(escapeChar) {
      var str = 'a ' + escapeChar + ' string escaped';
      var escaped = _.escape(str);
      notEqual(str, escaped, escapeChar + ' is escaped');
      equal(str, _.unescape(escaped), escapeChar + ' can be unescaped');

      str = 'a ' + escapeChar + escapeChar + escapeChar + 'some more string' + escapeChar;
      escaped = _.escape(str);

      equal(escaped.indexOf(escapeChar), -1, 'can escape multiple occurances of ' + escapeChar);
      equal(_.unescape(escaped), str, 'multiple occurrences of ' + escapeChar + ' can be unescaped');
    });

    // handles multiple escape characters at once
    var joiner = ' other stuff ';
    var allEscaped = escapeCharacters.join(joiner);
    allEscaped += allEscaped;
    ok(_.every(escapeCharacters, function(escapeChar) {
      return allEscaped.indexOf(escapeChar) !== -1;
    }), 'handles multiple characters');
    ok(allEscaped.indexOf(joiner) >= 0, 'can escape multiple escape characters at the same time');

    // test & -> &amp;
    var str = 'some string & another string & yet another';
    var escaped = _.escape(str);

    ok(escaped.indexOf('&') !== -1, 'handles & aka &amp;');
    equal(_.unescape(str), str, 'can unescape &amp;');
  });

  test('template', function() {
    var basicTemplate = _.template("<%= thing %> is gettin' on my noives!");
    var result = basicTemplate({thing : 'This'});
    equal(result, "This is gettin' on my noives!", 'can do basic attribute interpolation');

    var sansSemicolonTemplate = _.template('A <% this %> B');
    equal(sansSemicolonTemplate(), 'A  B');

    var backslashTemplate = _.template('<%= thing %> is \\ridanculous');
    equal(backslashTemplate({thing: 'This'}), 'This is \\ridanculous');

    var escapeTemplate = _.template('<%= a ? "checked=\\"checked\\"" : "" %>');
    equal(escapeTemplate({a: true}), 'checked="checked"', 'can handle slash escapes in interpolations.');

    var fancyTemplate = _.template('<ul><% ' +
    '  for (var key in people) { ' +
    '%><li><%= people[key] %></li><% } %></ul>');
    result = fancyTemplate({people : {moe : 'Moe', larry : 'Larry', curly : 'Curly'}});
    equal(result, '<ul><li>Moe</li><li>Larry</li><li>Curly</li></ul>', 'can run arbitrary javascript in templates');

    var escapedCharsInJavascriptTemplate = _.template('<ul><% _.each(numbers.split("\\n"), function(item) { %><li><%= item %></li><% }) %></ul>');
    result = escapedCharsInJavascriptTemplate({numbers: 'one\ntwo\nthree\nfour'});
    equal(result, '<ul><li>one</li><li>two</li><li>three</li><li>four</li></ul>', 'Can use escaped characters (e.g. \\n) in JavaScript');

    var namespaceCollisionTemplate = _.template('<%= pageCount %> <%= thumbnails[pageCount] %> <% _.each(thumbnails, function(p) { %><div class="thumbnail" rel="<%= p %>"></div><% }); %>');
    result = namespaceCollisionTemplate({
      pageCount: 3,
      thumbnails: {
        1: 'p1-thumbnail.gif',
        2: 'p2-thumbnail.gif',
        3: 'p3-thumbnail.gif'
      }
    });
    equal(result, '3 p3-thumbnail.gif <div class="thumbnail" rel="p1-thumbnail.gif"></div><div class="thumbnail" rel="p2-thumbnail.gif"></div><div class="thumbnail" rel="p3-thumbnail.gif"></div>');

    var noInterpolateTemplate = _.template('<div><p>Just some text. Hey, I know this is silly but it aids consistency.</p></div>');
    result = noInterpolateTemplate();
    equal(result, '<div><p>Just some text. Hey, I know this is silly but it aids consistency.</p></div>');

    var quoteTemplate = _.template("It's its, not it's");
    equal(quoteTemplate({}), "It's its, not it's");

    var quoteInStatementAndBody = _.template('<% ' +
    "  if(foo == 'bar'){ " +
    "%>Statement quotes and 'quotes'.<% } %>");
    equal(quoteInStatementAndBody({foo: 'bar'}), "Statement quotes and 'quotes'.");

    var withNewlinesAndTabs = _.template('This\n\t\tis: <%= x %>.\n\tok.\nend.');
    equal(withNewlinesAndTabs({x: 'that'}), 'This\n\t\tis: that.\n\tok.\nend.');

    var template = _.template('<i><%- value %></i>');
    result = template({value: '<script>'});
    equal(result, '<i>&lt;script&gt;</i>');

    var stooge = {
      name: 'Moe',
      template: _.template("I'm <%= this.name %>")
    };
    equal(stooge.template(), "I'm Moe");

    template = _.template('\n ' +
    '  <%\n ' +
    '  // a comment\n ' +
    '  if (data) { data += 12345; }; %>\n ' +
    '  <li><%= data %></li>\n '
    );
    equal(template({data : 12345}).replace(/\s/g, ''), '<li>24690</li>');

    _.templateSettings = {
      evaluate    : /\{\{([\s\S]+?)\}\}/g,
      interpolate : /\{\{=([\s\S]+?)\}\}/g
    };

    var custom = _.template('<ul>{{ for (var key in people) { }}<li>{{= people[key] }}</li>{{ } }}</ul>');
    result = custom({people : {moe : 'Moe', larry : 'Larry', curly : 'Curly'}});
    equal(result, '<ul><li>Moe</li><li>Larry</li><li>Curly</li></ul>', 'can run arbitrary javascript in templates');

    var customQuote = _.template("It's its, not it's");
    equal(customQuote({}), "It's its, not it's");

    quoteInStatementAndBody = _.template("{{ if(foo == 'bar'){ }}Statement quotes and 'quotes'.{{ } }}");
    equal(quoteInStatementAndBody({foo: 'bar'}), "Statement quotes and 'quotes'.");

    _.templateSettings = {
      evaluate    : /<\?([\s\S]+?)\?>/g,
      interpolate : /<\?=([\s\S]+?)\?>/g
    };

    var customWithSpecialChars = _.template('<ul><? for (var key in people) { ?><li><?= people[key] ?></li><? } ?></ul>');
    result = customWithSpecialChars({people : {moe : 'Moe', larry : 'Larry', curly : 'Curly'}});
    equal(result, '<ul><li>Moe</li><li>Larry</li><li>Curly</li></ul>', 'can run arbitrary javascript in templates');

    var customWithSpecialCharsQuote = _.template("It's its, not it's");
    equal(customWithSpecialCharsQuote({}), "It's its, not it's");

    quoteInStatementAndBody = _.template("<? if(foo == 'bar'){ ?>Statement quotes and 'quotes'.<? } ?>");
    equal(quoteInStatementAndBody({foo: 'bar'}), "Statement quotes and 'quotes'.");

    _.templateSettings = {
      interpolate : /\{\{(.+?)\}\}/g
    };

    var mustache = _.template('Hello {{planet}}!');
    equal(mustache({planet : 'World'}), 'Hello World!', 'can mimic mustache.js');

    var templateWithNull = _.template('a null undefined {{planet}}');
    equal(templateWithNull({planet : 'world'}), 'a null undefined world', 'can handle missing escape and evaluate settings');
  });

  test('_.template provides the generated function source, when a SyntaxError occurs', function() {
    try {
      _.template('<b><%= if x %></b>');
    } catch (ex) {
      var source = ex.source;
    }
    ok(/__p/.test(source));
  });

  test('_.template handles \\u2028 & \\u2029', function() {
    var tmpl = _.template('<p>\u2028<%= "\\u2028\\u2029" %>\u2029</p>');
    strictEqual(tmpl(), '<p>\u2028\u2028\u2029\u2029</p>');
  });

  test('result calls functions and returns primitives', function() {
    var obj = {w: '', x: 'x', y: function(){ return this.x; }};
    strictEqual(_.result(obj, 'w'), '');
    strictEqual(_.result(obj, 'x'), 'x');
    strictEqual(_.result(obj, 'y'), 'x');
    strictEqual(_.result(obj, 'z'), undefined);
    strictEqual(_.result(null, 'x'), undefined);
  });

  test('_.templateSettings.variable', function() {
    var s = '<%=data.x%>';
    var data = {x: 'x'};
    var tmp = _.template(s, {variable: 'data'});
    strictEqual(tmp(data), 'x');
    _.templateSettings.variable = 'data';
    strictEqual(_.template(s)(data), 'x');
  });

  test('#547 - _.templateSettings is unchanged by custom settings.', function() {
    ok(!_.templateSettings.variable);
    _.template('', {}, {variable: 'x'});
    ok(!_.templateSettings.variable);
  });

  test('#556 - undefined template variables.', function() {
    var template = _.template('<%=x%>');
    strictEqual(template({x: null}), '');
    strictEqual(template({x: undefined}), '');

    var templateEscaped = _.template('<%-x%>');
    strictEqual(templateEscaped({x: null}), '');
    strictEqual(templateEscaped({x: undefined}), '');

    var templateWithProperty = _.template('<%=x.foo%>');
    strictEqual(templateWithProperty({x: {}}), '');
    strictEqual(templateWithProperty({x: {}}), '');

    var templateWithPropertyEscaped = _.template('<%-x.foo%>');
    strictEqual(templateWithPropertyEscaped({x: {}}), '');
    strictEqual(templateWithPropertyEscaped({x: {}}), '');
  });

  test('interpolate evaluates code only once.', 2, function() {
    var count = 0;
    var template = _.template('<%= f() %>');
    template({f: function(){ ok(!count++); }});

    var countEscaped = 0;
    var templateEscaped = _.template('<%- f() %>');
    templateEscaped({f: function(){ ok(!countEscaped++); }});
  });

  test('#746 - _.template settings are not modified.', 1, function() {
    var settings = {};
    _.template('', null, settings);
    deepEqual(settings, {});
  });

  test('#779 - delimeters are applied to unescaped text.', 1, function() {
    var template = _.template('<<\nx\n>>', null, {evaluate: /<<(.*?)>>/g});
    strictEqual(template(), '<<\nx\n>>');
  });

}());