Cover with js unit test, static test fix

Author: Nazar65

app/code/Magento/Tinymce3/view/base/web/tinymce3Adapter.js

@@ -78,8 +78,8 @@ define([
             }
 
             tinyMCE3.init(this.getSettings(mode));
-            varienGlobalEvents.clearEventHandlers("open_browser_callback");
-            varienGlobalEvents.attachEventHandler("open_browser_callback", tinyMceEditors.get(this.id).openFileBrowser);
+            varienGlobalEvents.clearEventHandlers('open_browser_callback');
+            varienGlobalEvents.attachEventHandler('open_browser_callback', tinyMceEditors.get(this.id).openFileBrowser);
         },
 
         /**

dev/tests/js/jasmine/tests/lib/mage/tinymce4Adapter.test.js

@@ -0,0 +1,41 @@
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+define([
+    'wysiwygAdapter',
+    'underscore'
+], function (wysiwygAdapter, _) {
+    'use strict';
+
+    var obj;
+
+    beforeEach(function () {
+
+        /**
+         * Dummy constructor to use for instantiation
+         * @constructor
+         */
+        var Constr = function () {};
+
+        Constr.prototype = wysiwygAdapter;
+
+        obj = new Constr();
+        obj.eventBus = new window.varienEvents();
+        obj.initialize(1, {
+            'store_id': 0,
+            'tinymce4': {
+                'content_css': ''
+            },
+            'files_browser_window_url': 'url'
+        });
+        obj.setup();
+    });
+
+    describe('"openFileBrowser" method', function () {
+        it('Opens file browser to given instance', function () {
+            expect(_.size(obj.eventBus.arrEvents['open_browser_callback'])).toBe(1);
+        });
+    });
+});

lib/internal/Magento/Framework/Data/Form/Element/Editor.php

@@ -310,9 +310,7 @@ protected function _getPluginButtonsHtml($visible = true)
                         if (isset($buttonOptions['style'])) {
                             $configStyle = $buttonOptions['style'];
                         }
-                        // phpcs:disable Magento2.Performance.ForeachArrayMerge
-                        $buttonOptions = array_merge($buttonOptions, ['style' => 'display:none;' . $configStyle]);
-                        // phpcs:enable
+                        $buttonOptions['style'] = 'display:none; ' . $configStyle;
                     }
                     $buttonsHtml .= $this->_getButtonHtml($buttonOptions);
                 }