adding basic unit test for failing file_put_content operation

tests/lib/connector/sabre/file.php

+<?php
+/**
+ * Copyright (c) 2013 Thomas Müller <thomas.mueller@tmit.eu>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+class Test_OC_Connector_Sabre_File extends PHPUnit_Framework_TestCase {
+
+	public function setUp() {
+	}
+
+	/**
+	 * @expectedException Sabre_DAV_Exception
+	 */
+	public function testSimplePutFails() {
+		// setup
+		$file = new OC_Connector_Sabre_File('/test.txt');
+		$file->fileView = $this->getMock('\OC\Files\View', array('file_put_contents'), array(), '', FALSE);
+		$file->fileView->expects($this->any())->method('file_put_contents')->withAnyParameters()->will($this->returnValue(false));
+
+		// action
+		$etag = $file->put('test data');
+	}
+
+}