add mutation observer polyfill for jest test env (#20996) (#21409)

* add mutation observer polyfill for jest test env

* use polyfill from npm

* set bluebird scheduler

* use correct version in comment about bluebird

package.json

@@ -324,6 +324,7 @@
     "mocha": "3.3.0",
     "mock-fs": "^4.4.2",
     "murmurhash3js": "3.0.1",
+    "mutation-observer": "^1.0.3",
     "ncp": "2.0.0",
     "nock": "8.0.0",
     "node-sass": "^4.9.0",

src/core_plugins/input_control_vis/public/components/editor/controls_tab.test.js

@@ -96,18 +96,6 @@ test('renders ControlsTab', () => {
 });
 
 describe('behavior', () => {
-  // Mock MutationObserver used in EuiAccordion
-  beforeAll(() => {
-    global.MutationObserver = class {
-      constructor() {}
-      disconnect() {}
-      observe() {}
-    };
-  });
-
-  afterAll(() => {
-    delete global.MutationObserver;
-  });
 
   test('add control button', () => {
     const component = mount(<ControlsTab

src/dev/jest/config.js

@@ -48,6 +48,7 @@ export default {
   },
   setupFiles: [
     '<rootDir>/src/dev/jest/setup/babel_polyfill.js',
+    '<rootDir>/src/dev/jest/setup/polyfills.js',
     '<rootDir>/src/dev/jest/setup/enzyme.js',
     '<rootDir>/src/dev/jest/setup/throw_on_console_error.js',
   ],

src/dev/jest/setup/polyfills.js

@@ -0,0 +1,26 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+// bluebird < v3.3.5 does not work with MutationObserver polyfill
+// when MutationObserver exists, bluebird avoids using node's builtin async schedulers
+const bluebird = require('bluebird');
+bluebird.Promise.setScheduler(function (fn) { global.setImmediate.call(global, fn); });
+
+const MutationObserver = require('mutation-observer');
+Object.defineProperty(window, 'MutationObserver', { value: MutationObserver });

x-pack/dev-tools/jest/create_jest_config.js

@@ -28,7 +28,8 @@ export function createJestConfig({
     },
     setupFiles: [
       `${kibanaDirectory}/src/dev/jest/setup/babel_polyfill.js`,
-      `<rootDir>/dev-tools/jest/setup/enzyme.js`
+      `<rootDir>/dev-tools/jest/setup/polyfills.js`,
+      `<rootDir>/dev-tools/jest/setup/enzyme.js`,
     ],
     testMatch: [
       "**/*.test.{js,ts,tsx}"

x-pack/dev-tools/jest/setup/polyfills.js

@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+// bluebird < v3.3.5 does not work with MutationObserver polyfill
+// when MutationObserver exists, bluebird avoids using node's builtin async schedulers
+// x-pack has a different version of bluebird so it needs its own polyfills.js to ensure
+// the scheduler is set on the right bluebird instance
+const bluebird = require('bluebird');
+bluebird.Promise.setScheduler(function (fn) { global.setImmediate.call(global, fn); });
+
+const MutationObserver = require('mutation-observer');
+Object.defineProperty(window, 'MutationObserver', { value: MutationObserver });

x-pack/package.json

@@ -57,6 +57,7 @@
     "jest-styled-components": "^5.0.1",
     "mocha": "3.3.0",
     "mustache": "^2.3.0",
+    "mutation-observer": "^1.0.3",
     "node-fetch": "^2.1.2",
     "pdf-image": "1.1.0",
     "pixelmatch": "4.0.2",

x-pack/yarn.lock

@@ -5455,6 +5455,10 @@ mustache@^2.3.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/mustache/-/mustache-2.3.0.tgz#4028f7778b17708a489930a6e52ac3bca0da41d0"
 
+mutation-observer@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/mutation-observer/-/mutation-observer-1.0.3.tgz#42e9222b101bca82e5ba9d5a7acf4a14c0f263d0"
+
 mute-stream@0.0.6:
   version "0.0.6"
   resolved "https://registry.yarnpkg.com/mute-stream/-/mute-stream-0.0.6.tgz#48962b19e169fd1dfc240b3f1e7317627bbc47db"

yarn.lock

@@ -9216,6 +9216,10 @@ mustache@2.3.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/mustache/-/mustache-2.3.0.tgz#4028f7778b17708a489930a6e52ac3bca0da41d0"
 
+mutation-observer@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/mutation-observer/-/mutation-observer-1.0.3.tgz#42e9222b101bca82e5ba9d5a7acf4a14c0f263d0"
+
 mute-stream@0.0.5:
   version "0.0.5"
   resolved "https://registry.yarnpkg.com/mute-stream/-/mute-stream-0.0.5.tgz#8fbfabb0a98a253d3184331f9e8deb7372fac6c0"