Implemented group cache delete in FileEngine

lib/Cake/Cache/Engine/FileEngine.php

@@ -351,7 +351,20 @@ class FileEngine extends CacheEngine {
 		return $key;
 	}
 
+/**
+ * Recursively deletes all files under any directory named as $group
+ *
+ * @return boolean success
+ **/
 	public function clearGroup($group) {
-
+		$directoryIterator = new RecursiveDirectoryIterator($this->settings['path']);
+		$contents = new RecursiveIteratorIterator($directoryIterator, RecursiveIteratorIterator::CHILD_FIRST);
+		foreach ($contents as $object) {
+			$containsGroup = strpos($object->getPathName(), DS . $group . DS) !== false;
+			if ($object->isFile() && $containsGroup) {
+				unlink($object->getPathName());
+			}
+		}
+		return true;
 	}
 }

lib/Cake/Test/Case/Cache/Engine/FileEngineTest.php

@@ -54,6 +54,8 @@ class FileEngineTest extends CakeTestCase {
 		Cache::clear(false, 'file_test');
 		Cache::drop('file_test');
 		Cache::drop('file_groups');
+		Cache::drop('file_groups2');
+		Cache::drop('file_groups3');
 	}
 
 /**
@@ -422,4 +424,32 @@ class FileEngineTest extends CakeTestCase {
 		$this->assertFalse(Cache::read('test_groups', 'file_groups'));
 	}
 
+/**
+ * Test clearing a cache group
+ *
+ * @return void
+ **/
+	public function testGroupClear() {
+		Cache::config('file_groups', array('engine' => 'File', 'duration' => 3600, 'groups' => array('group_a', 'group_b')));
+		Cache::config('file_groups2', array('engine' => 'File', 'duration' => 3600, 'groups' => array('group_b')));
+		Cache::config('file_groups3', array('engine' => 'File', 'duration' => 3600, 'groups' => array('group_a')));
+
+		$this->assertTrue(Cache::write('test_groups', 'value', 'file_groups'));
+		$this->assertTrue(Cache::write('test_groups2', 'value', 'file_groups2'));
+		$this->assertTrue(Cache::write('test_groups3', 'value', 'file_groups3'));
+
+		$this->assertTrue(Cache::clearGroup('group_a', 'file_groups'));
+		$this->assertFalse(Cache::read('test_groups', 'file_groups'));
+		$this->assertEquals('value', Cache::read('test_groups2', 'file_groups2'));
+		$this->assertFalse(Cache::read('test_groups3', 'file_groups3'));
+
+		$this->assertTrue(Cache::write('test_groups4', 'value', 'file_groups'));
+		$this->assertTrue(Cache::write('test_groups5', 'value', 'file_groups2'));
+		$this->assertTrue(Cache::write('test_groups6', 'value', 'file_groups3'));
+
+		$this->assertTrue(Cache::clearGroup('group_b', 'file_groups'));
+		$this->assertFalse(Cache::read('test_groups4', 'file_groups'));
+		$this->assertFalse(Cache::read('test_groups5', 'file_groups2'));
+		$this->assertEquals('value', Cache::read('test_groups6', 'file_groups3'));
+	}
 }