[MAINTENANCE] Add test for IiifUrlReader (kitodo#909)

Tests/Fixtures/Common/correct.txt

@@ -0,0 +1 @@
+Correct result

Tests/Functional/Common/IiifUrlReaderTest.php

@@ -0,0 +1,34 @@
+<?php
+/**
+ * (c) Kitodo. Key to digital objects e.V. <[email protected]>
+ *
+ * This file is part of the Kitodo and TYPO3 projects.
+ *
+ * @license GNU General Public License version 3 or later.
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ */
+
+namespace Kitodo\Dlf\Tests\Functional\Common;
+
+use Kitodo\Dlf\Common\IiifUrlReader;
+use Kitodo\Dlf\Tests\Functional\FunctionalTestCase;
+
+class IiifUrlReaderTest extends FunctionalTestCase
+{
+    /**
+     * @test
+     * @group getContent
+     */
+    public function getContentCheck()
+    {
+        $iiifUrlReader = new IiifUrlReader();
+
+        $correctUrl = 'http://web:8001/Tests/Fixtures/Common/correct.txt';
+        $expected = "Correct result\n";
+        $this->assertSame($expected, $iiifUrlReader->getContent($correctUrl));
+
+        $incorrectUrl = 'http://web:8001/incorrectPath';
+        $this->assertSame('', $iiifUrlReader->getContent($incorrectUrl));
+    }
+}