public function testRemove()
 {
     CMSMenu::clear_menu();
     CMSMenu::add_menu_item('custom', 'Custom Title', 'custom');
     CMSMenu::add_menu_item('other', 'Other Section', 'other', 'CMSMenuTest_LeftAndMainController');
     $this->assertNotEmpty(CMSMenu::get_menu_items());
     CMSMenu::remove_menu_class('CMSMenuTest_LeftAndMainController');
     CMSMenu::remove_menu_item('custom');
     $this->assertEmpty(CMSMenu::get_menu_items());
 }
<?php

use SilverStripe\Admin\CMSMenu;
use SilverStripe\Forms\HTMLEditor\TinyMCEConfig;
// Default CMS HTMLEditorConfig
TinyMCEConfig::get('cms')->setOptions(array('friendly_name' => 'Default CMS', 'priority' => '50', 'body_class' => 'typography', 'contextmenu' => "sslink ssmedia inserttable | cell row column deletetable", 'use_native_selects' => false, 'valid_elements' => "@[id|class|style|title],a[id|rel|rev|dir|tabindex|accesskey|type|name|href|target|title" . "|class],-strong/-b[class],-em/-i[class],-strike[class],-u[class],#p[id|dir|class|align|style],-ol[class]," . "-ul[class],-li[class],br,img[id|dir|longdesc|usemap|class|src|border|alt=|title|width|height|align|data*]," . "-sub[class],-sup[class],-blockquote[dir|class],-cite[dir|class|id|title]," . "-table[cellspacing|cellpadding|width|height|class|align|summary|dir|id|style]," . "-tr[id|dir|class|rowspan|width|height|align|valign|bgcolor|background|bordercolor|style]," . "tbody[id|class|style],thead[id|class|style],tfoot[id|class|style]," . "#td[id|dir|class|colspan|rowspan|width|height|align|valign|scope|style]," . "-th[id|dir|class|colspan|rowspan|width|height|align|valign|scope|style],caption[id|dir|class]," . "-div[id|dir|class|align|style],-span[class|align|style],-pre[class|align],address[class|align]," . "-h1[id|dir|class|align|style],-h2[id|dir|class|align|style],-h3[id|dir|class|align|style]," . "-h4[id|dir|class|align|style],-h5[id|dir|class|align|style],-h6[id|dir|class|align|style],hr[class]," . "dd[id|class|title|dir],dl[id|class|title|dir],dt[id|class|title|dir]", 'extended_valid_elements' => "img[class|src|alt|title|hspace|vspace|width|height|align|onmouseover|onmouseout|name" . "|usemap|data*],iframe[src|name|width|height|align|frameborder|marginwidth|marginheight|scrolling]," . "object[width|height|data|type],param[name|value],map[class|name|id],area[shape|coords|href|target|alt]"));
TinyMCEConfig::get('cms')->enablePlugins(array('contextmenu' => null, 'image' => null, 'ssbuttons' => FRAMEWORK_ADMIN_DIR . '/client/dist/js/TinyMCE_SSPlugin.js'));
CMSMenu::remove_menu_class('SilverStripe\\Admin\\CMSProfileController');