Updated page navigation logic to ignore empty headers

Fixes #1429

tests/Unit/PageRepoTest.php

@@ -0,0 +1,32 @@
+<?php
+namespace Tests;
+
+use BookStack\Entities\Repos\PageRepo;
+
+class PageRepoTest extends TestCase
+{
+    /**
+     * @var PageRepo $pageRepo
+     */
+    protected $pageRepo;
+
+    protected function setUp()
+    {
+        parent::setUp();
+        $this->pageRepo = app()->make(PageRepo::class);
+    }
+
+    public function test_get_page_nav_does_not_show_empty_titles()
+    {
+        $content = '<h1 id="testa">Hello</h1><h2 id="testb">&nbsp;</h2><h3 id="testc"></h3>';
+        $navMap = $this->pageRepo->getPageNav($content);
+
+        $this->assertCount(1, $navMap);
+        $this->assertArraySubset([
+            'nodeName' => 'h1',
+            'link' => '#testa',
+            'text' => 'Hello'
+        ], $navMap[0]);
+    }
+
+}