Adds default value parameter to the env() function.

src/Core/functions.php

@@ -176,10 +176,11 @@ if (!function_exists('env')) {
      * environment information.
      *
      * @param string $key Environment variable name.
+     * @param string $default Specify a default value in case the environment variable is not defined.
      * @return string|null Environment variable setting.
      * @link http://book.cakephp.org/3.0/en/core-libraries/global-constants-and-functions.html#env
      */
-    function env($key)
+    function env($key, $default = null)
     {
         if ($key === 'HTTPS') {
             if (isset($_SERVER['HTTPS'])) {
@@ -228,7 +229,7 @@ if (!function_exists('env')) {
             case 'CGI_MODE':
                 return (PHP_SAPI === 'cgi');
         }
-        return null;
+        return $default;
     }
 
 }

tests/TestCase/Core/FunctionsTest.php

@@ -0,0 +1,50 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link          http://cakephp.org CakePHP(tm) Project
+ * @since         3.0.0
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Test\TestCase\Core;
+
+use Cake\TestSuite\TestCase;
+
+/**
+ * Test cases for functions in Core\functions.php
+ */
+class FunctionsTest extends TestCase
+{
+    /**
+     * Test cases for env()
+     */
+    public function testEnv()
+    {
+        $_ENV['DOES_NOT_EXIST'] = null;
+        $actual = env('DOES_NOT_EXIST');
+        $this->assertNull($actual);
+        $actual = env('DOES_NOT_EXIST', 'default');
+        $this->assertEquals('default', $actual);
+        $_ENV['DOES_EXIST'] = 'some value';
+        $actual = env('DOES_EXIST');
+        $this->assertEquals('some value', $actual);
+        $actual = env('DOES_EXIST', 'default');
+        $this->assertEquals('some value', $actual);
+        $_ENV['EMPTY_VALUE'] = '';
+        $actual = env('EMPTY_VALUE');
+        $this->assertEquals('', $actual);
+        $actuaal = env('EMPTY_VALUE', 'default');
+        $this->assertEquals('', $actual);
+        $_ENV['ZERO'] = '0';
+        $actual = env('ZERO');
+        $this->assertEquals('0', $actual);
+        $actual = env('ZERO', '1');
+        $this->assertEquals('0', $actual);
+    }
+}