Created ArrayCache class

- can be used to enable caching in a request without the need for any storage
- useful for example in complex console tasks that should still be independed

tests/unit/framework/caching/ArrayCacheTest.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace yiiunit\framework\caching;
+
+use yii\caching\ArrayCache;
+
+/**
+ * Class for testing file cache backend
+ * @group caching
+ */
+class ArrayCacheTest extends CacheTestCase
+{
+    private $_cacheInstance = null;
+
+    /**
+     * @return ArrayCache
+     */
+    protected function getCacheInstance()
+    {
+        if ($this->_cacheInstance === null) {
+            $this->_cacheInstance = new ArrayCache();
+        }
+        return $this->_cacheInstance;
+    }
+
+    public function testExpire()
+    {
+        $cache = $this->getCacheInstance();
+
+        static::$microtime = \microtime(true);
+        $this->assertTrue($cache->set('expire_test', 'expire_test', 2));
+        static::$microtime++;
+        $this->assertEquals('expire_test', $cache->get('expire_test'));
+        static::$microtime++;
+        $this->assertFalse($cache->get('expire_test'));
+    }
+
+    public function testExpireAdd()
+    {
+        $cache = $this->getCacheInstance();
+
+        static::$microtime = \microtime(true);
+        $this->assertTrue($cache->add('expire_testa', 'expire_testa', 2));
+        static::$microtime++;
+        $this->assertEquals('expire_testa', $cache->get('expire_testa'));
+        static::$microtime++;
+        $this->assertFalse($cache->get('expire_testa'));
+    }
+}