Add a CascadingLoader implementation.

test/Mustache/Test/Loader/CascadingLoaderTest.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * @group unit
+ */
+class Mustache_Test_Loader_CascadingLoaderTest extends PHPUnit_Framework_TestCase
+{
+    public function testLoadTemplates()
+    {
+        $loader = new Mustache_Loader_CascadingLoader(array(
+            new Mustache_Loader_ArrayLoader(array('foo' => '{{ foo }}')),
+            new Mustache_Loader_ArrayLoader(array('bar' => '{{#bar}}BAR{{/bar}}')),
+        ));
+
+        $this->assertEquals('{{ foo }}', $loader->load('foo'));
+        $this->assertEquals('{{#bar}}BAR{{/bar}}', $loader->load('bar'));
+    }
+
+    /**
+     * @expectedException Mustache_Exception_UnknownTemplateException
+     */
+    public function testMissingTemplatesThrowExceptions()
+    {
+        $loader = new Mustache_Loader_CascadingLoader(array(
+            new Mustache_Loader_ArrayLoader(array('foo' => '{{ foo }}')),
+            new Mustache_Loader_ArrayLoader(array('bar' => '{{#bar}}BAR{{/bar}}')),
+        ));
+
+        $loader->load('not_a_real_template');
+    }
+}