Add reference implementation and basic test setup

Uses especially for the reference implementation.

Closes #2, although as per #1 the TDD plan is not workable anymore.

.gitignore

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+/node_modules/

package.json

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+{
+  "name": "array.prototype.contains",
+  "version": "1.0.0",
+  "description": "Tests and a polyfill for the ES proposal for Array.prototype.contains",
+  "main": "reference-implementation/index.js",
+  "scripts": {
+    "test": "test262-harness --prelude=reference-implementation/index.js --consoleCommand=\"node --harmony\" --runner=console --reporter=tap test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/domenic/Array.prototype.contains.git"
+  },
+  "keywords": [
+    "ecmascript",
+    "array",
+    "test262",
+    "contains"
+  ],
+  "author": "Domenic Denicola <domenic@domenicdenicola.com> (http://domenic.me/)",
+  "license": "BSD-2-Clause",
+  "devDependencies": {
+    "test262-harness": "bterlson/test262-harness"
+  },
+  "dependencies": {
+    "especially": "^1.6.0"
+  }
+}

reference-implementation/index.js

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+"use strict";
+
+var Get = require("especially/abstract-operations").Get;
+var HasProperty = require("especially/abstract-operations").HasProperty;
+var SameValueZero = require("especially/abstract-operations").SameValueZero;
+var ToInteger = require("especially/abstract-operations").ToInteger;
+var ToLength = require("especially/abstract-operations").ToLength;
+var ToObject = require("especially/abstract-operations").ToObject;
+var ToString = require("especially/abstract-operations").ToString;
+var abs = require("especially/math").abs;
+
+Array.prototype.contains = function (searchElement) {
+    var fromIndex = arguments[1];
+
+    var O = ToObject(this);
+    var len = ToLength(Get(O, "length"));
+
+    if (len === 0) {
+        return false;
+    }
+
+    var n = ToInteger(fromIndex);
+
+    if (n >= len) {
+        return false;
+    }
+
+    var k;
+    if (n >= 0) {
+        k = n;
+    } else {
+        k = len - abs(n);
+        if (k < 0) {
+            k = 0;
+        }
+    }
+
+    while (k < len) {
+        var kPresent = HasProperty(O, ToString(k));
+
+        if (kPresent === true) {
+            var elementK = Get(O, ToString(k));
+            if (SameValueZero(searchElement, elementK) === true) {
+                return true;
+            }
+        }
+
+        ++k;
+    }
+
+    return false;
+};

test/Array.prototype.contains_length.js

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+// Copyright (C) 2014 Domenic Denicola. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Array.prototype.contains should have length 1
+---*/
+
+if (Array.prototype.contains.length !== 1) {
+    $ERROR('Expected Array.prototype.contains.length to be 1');
+}

test/Array.prototype.contains_number-this.js

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+// Copyright (C) 2014 Domenic Denicola. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Array.prototype.contains should use ToObject on this, so that when
+             called with a number, it picks up numeric properties from
+             Number.prototype
+---*/
+
+Number.prototype[0] = "a";
+Number.prototype[1] = "b";
+Number.prototype.length = 2;
+
+var result1 = Array.prototype.contains.call(5, "a");
+if (result1 !== true) {
+    $ERROR('Expected 5 to contain "a"');
+}
+
+var result2 = Array.prototype.contains.call(5, "b");
+if (result2 !== true) {
+    $ERROR('Expected 5 to contain "b"');
+}
+
+var result3 = Array.prototype.contains.call(5, "c");
+if (result3 !== false) {
+    $ERROR('Expected 5 to not contain "c"');
+}

test/README.md

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+# `Array.prototype.contains` Tests
+
+These tests are written in test262 format. To run them against the reference implementation, do
+
+```bash
+$ npm install
+$ npm test
+```
+
+which will use the [bterlson/test262-harness](https://github.com/bterlson/test262-harness) runner.