testing: Added test unit for Docs (#8745)

* testing: Added test unit for Docs

* Update mkdocs.yml

* Avoid extra function

* contains -> diff

tests/DocsTest.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * DocTest.php
+ *
+ * Tests for Docs.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @package    LibreNMS
+ * @link       http://librenms.org
+ * @copyright  2018 Neil Lathwood
+ * @author     Neil Lathwood <gh+n@laf.io>
+ */
+
+namespace LibreNMS\Tests;
+
+use Symfony\Component\Yaml\Yaml;
+
+class DocTest extends TestCase
+{
+    public function testDocExist()
+    {
+        $mkdocs = Yaml::parse(file_get_contents(__DIR__ . '/../mkdocs.yml'));
+        $dir    = __DIR__ . '/../doc/';
+        $files  = str_replace($dir, '', rtrim(`find $dir -name '*.md'`));
+
+        // check for missing pages
+        collect(explode(PHP_EOL, $files))
+            ->diff(collect($mkdocs['pages'])->flatten()) // grab defined pages and diff
+            ->each(function ($missing_doc) {
+                $this->fail("The doc $missing_doc doesn't exist in mkdocs.yml, please add it to the relevant section");
+            });
+    }
+}