Fix timing issues in char width test

test/api/CharWidth.api.ts

@@ -4,8 +4,8 @@
  */
 
 import * as puppeteer from 'puppeteer';
-import { assert } from 'chai';
 import { ITerminalOptions } from 'xterm';
+import { pollFor } from './TestUtils';
 
 const APP = 'http://127.0.0.1:3000/test';
 
@@ -15,12 +15,9 @@ const width = 800;
 const height = 600;
 
 describe('CharWidth Integration Tests', function(): void {
-  this.timeout(20000);
-
   before(async function(): Promise<any> {
     browser = await puppeteer.launch({
       headless: process.argv.indexOf('--headless') !== -1,
-      slowMo: 0,
       args: [`--window-size=${width},${height}`, `--no-sandbox`]
     });
     page = (await browser.pages())[0];
@@ -41,37 +38,37 @@ describe('CharWidth Integration Tests', function(): void {
     it('ASCII chars', async function(): Promise<void> {
       const input = 'This is just ASCII text.#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(25, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 25);
     });
 
     it('combining chars', async function(): Promise<void> {
       const input = 'e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(10, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 10);
     });
 
     it('surrogate chars', async function(): Promise<void> {
       const input = '𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(28, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 28);
     });
 
     it('surrogate combining chars', async function(): Promise<void> {
       const input = '𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(12, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 12);
     });
 
     it('fullwidth chars', async function(): Promise<void> {
       const input = '１２３４５６７８９０#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(21, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 21);
     });
 
     it('fullwidth chars offset 1', async function(): Promise<void> {
       const input = 'a１２３４５６７８９０#';
       await page.evaluate(`window.term.write('${input}')`);
-      assert.equal(22, await sumWidths(0, 1, '#'));
+      await pollFor(page, () => sumWidths(0, 1, '#'), 22);
     });
 
     // TODO: multiline tests once #1685 is resolved

test/api/TestUtils.ts

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) 2019 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import * as puppeteer from 'puppeteer';
+
+export async function pollFor<T>(page: puppeteer.Page, evalOrFn: string | (() => Promise<T>), val: T, preFn?: () => Promise<void>): Promise<void> {
+  if (preFn) {
+    await preFn();
+  }
+  const result = typeof evalOrFn === 'string' ? await page.evaluate(evalOrFn) : await evalOrFn();
+  let equal = false;
+  if (typeof result === 'object') {
+    equal = Object.keys(result).every(e => result[e] === (val as any)[e]);
+  } else {
+    equal = result === val;
+  }
+  if (!equal) {
+    return new Promise<void>(r => {
+      setTimeout(() => r(pollFor(page, evalOrFn, val, preFn)), 10);
+    });
+  }
+}