Fix external link rendering and add test case

_test/inverse.test.php

@@ -0,0 +1,27 @@
+<?php
+require_once DOKU_INC.'_test/lib/unittest.php';
+require_once DOKU_INC.'inc/init.php';
+require_once dirname(__FILE__) . '/../inverse.php';
+
+class edittable_test_inverse extends Doku_UnitTestCase {
+    function test() {
+        $this->externallink();
+    }
+
+    function externallink() {
+        $text = '[[file:///x:\folder\file.zip]]';
+        $this->render($text);
+    }
+
+    protected function render($text) {
+        $instructions = p_get_instructions($text);
+        $Renderer = new Doku_Renderer_wiki;
+
+        foreach ( $instructions as $instruction ) {
+            // Execute the callback against the Renderer
+            call_user_func_array(array(&$Renderer, $instruction[0]),$instruction[1]);
+        }
+
+        $this->assertEqual($Renderer->doc, $text);
+    }
+}