Remove waitForPromises in attachment_spec file

spec/frontend/content_editor/extensions/attachment_spec.js

 import axios from 'axios';
 import MockAdapter from 'axios-mock-adapter';
-import { once } from 'lodash';
-import waitForPromises from 'helpers/wait_for_promises';
 import Attachment from '~/content_editor/extensions/attachment';
 import Image from '~/content_editor/extensions/image';
 import Link from '~/content_editor/extensions/link';
@@ -12,7 +10,6 @@ import { createTestEditor, createDocBuilder } from '../test_utils';
 
 describe('content_editor/extensions/attachment', () => {
   let tiptapEditor;
-  let eq;
   let doc;
   let p;
   let image;
@@ -25,6 +22,24 @@ describe('content_editor/extensions/attachment', () => {
   const imageFile = new File(['foo'], 'test-file.png', { type: 'image/png' });
   const attachmentFile = new File(['foo'], 'test-file.zip', { type: 'application/zip' });
 
+  const expectDocumentAfterTransaction = ({ number, expectedDoc, action }) => {
+    return new Promise((resolve) => {
+      let counter = 1;
+      const handleTransaction = () => {
+        if (counter === number) {
+          expect(tiptapEditor.state.doc.toJSON()).toEqual(expectedDoc.toJSON());
+          tiptapEditor.off('update', handleTransaction);
+          resolve();
+        }
+
+        counter += 1;
+      };
+
+      tiptapEditor.on('update', handleTransaction);
+      action();
+    });
+  };
+
   beforeEach(() => {
     renderMarkdown = jest.fn();
 
@@ -34,7 +49,6 @@ describe('content_editor/extensions/attachment', () => {
 
     ({
       builders: { doc, p, image, loading, link },
-      eq,
     } = createDocBuilder({
       tiptapEditor,
       names: {
@@ -90,18 +104,14 @@ describe('content_editor/extensions/attachment', () => {
           mock.onPost().reply(httpStatus.OK, successResponse);
         });
 
-        it('inserts an image with src set to the encoded image file and uploading true', (done) => {
+        it('inserts an image with src set to the encoded image file and uploading true', async () => {
           const expectedDoc = doc(p(image({ uploading: true, src: base64EncodedFile })));
 
-          tiptapEditor.on(
-            'update',
-            once(() => {
-              expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
-              done();
-            }),
-          );
-
-          tiptapEditor.commands.uploadAttachment({ file: imageFile });
+          await expectDocumentAfterTransaction({
+            number: 1,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: imageFile }),
+          });
         });
 
         it('updates the inserted image with canonicalSrc when upload is successful', async () => {
@@ -116,11 +126,11 @@ describe('content_editor/extensions/attachment', () => {
             ),
           );
 
-          tiptapEditor.commands.uploadAttachment({ file: imageFile });
-
-          await waitForPromises();
-
-          expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
+          await expectDocumentAfterTransaction({
+            number: 2,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: imageFile }),
+          });
         });
       });
 
@@ -129,14 +139,14 @@ describe('content_editor/extensions/attachment', () => {
           mock.onPost().reply(httpStatus.INTERNAL_SERVER_ERROR);
         });
 
-        it('resets the doc to orginal state', async () => {
+        it('resets the doc to original state', async () => {
           const expectedDoc = doc(p(''));
 
-          tiptapEditor.commands.uploadAttachment({ file: imageFile });
-
-          await waitForPromises();
-
-          expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
+          await expectDocumentAfterTransaction({
+            number: 2,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: imageFile }),
+          });
         });
 
         it('emits an error event that includes an error message', (done) => {
@@ -168,18 +178,14 @@ describe('content_editor/extensions/attachment', () => {
           mock.onPost().reply(httpStatus.OK, successResponse);
         });
 
-        it('inserts a loading mark', (done) => {
+        it('inserts a loading mark', async () => {
           const expectedDoc = doc(p(loading({ label: 'test-file' })));
 
-          tiptapEditor.on(
-            'update',
-            once(() => {
-              expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
-              done();
-            }),
-          );
-
-          tiptapEditor.commands.uploadAttachment({ file: attachmentFile });
+          await expectDocumentAfterTransaction({
+            number: 1,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: attachmentFile }),
+          });
         });
 
         it('updates the loading mark with a link with canonicalSrc and href attrs', async () => {
@@ -196,11 +202,11 @@ describe('content_editor/extensions/attachment', () => {
             ),
           );
 
-          tiptapEditor.commands.uploadAttachment({ file: attachmentFile });
-
-          await waitForPromises();
-
-          expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
+          await expectDocumentAfterTransaction({
+            number: 2,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: attachmentFile }),
+          });
         });
       });
 
@@ -212,11 +218,11 @@ describe('content_editor/extensions/attachment', () => {
         it('resets the doc to orginal state', async () => {
           const expectedDoc = doc(p(''));
 
-          tiptapEditor.commands.uploadAttachment({ file: attachmentFile });
-
-          await waitForPromises();
-
-          expect(eq(tiptapEditor.state.doc, expectedDoc)).toBe(true);
+          await expectDocumentAfterTransaction({
+            number: 2,
+            expectedDoc,
+            action: () => tiptapEditor.commands.uploadAttachment({ file: attachmentFile }),
+          });
         });
 
         it('emits an error event that includes an error message', (done) => {