javascript - 为什么我在使用 Selenium-webdriver 运行测试时不断收到“UnhandledPromiseRejectionWarning”？

Question

我正在尝试在我的前端使用和不使用 mocha 的 Selenium 测试，在我构建的 i React 应用程序上。但我不断收到错误。摩卡咖啡运行所以硒有问题吗？

在具有以下版本的 MacOS 上：

"mocha": "^6.2.2",
"selenium-webdriver": "^4.0.0-alpha.5"
"geckodriver": "^1.19.1",
"safari": "0.0.1"

这只是一个开始，一个非常简单的返回应用程序标题的测试。

该应用程序已启动并运行http://localhost:3000/

我尝试过不同的浏览器；火狐和野生动物园。它们都打开了，但它们都（最终）返回相同的错误。

在 test/src 中运行测试node SimpleTest.js

这是 SimpleTest.js

var webdriver = require("selenium-webdriver");
const serverUri = "http://localhost:3000";

var browser = new webdriver.Builder()
    .withCapabilities(webdriver.Capabilities.firefox())
    .build();

browser.get(serverUri);

browser.getTitle()
    .then(function (title) {
        console.log("The title", title);
    });

browser.quit();

我期望的输出

$ node SimpleTest.js 
The title Me-Me-Me

但我得到了

$ node SimpleTest.js 
The title 
(node:1582) UnhandledPromiseRejectionWarning: NoSuchSessionError: Tried to run command without establishing a connection
    at Object.throwDecodedError (/$HOME/jsramverk/node_modules/selenium-webdriver/lib/error.js:550:15)
    at parseHttpResponse (/$HOME/jsramverk/node_modules/selenium-webdriver/lib/http.js:563:13)
    at Executor.execute (//$HOME/jsramverk/node_modules/selenium-webdriver/lib/http.js:489:26)
    at process._tickCallback (internal/process/next_tick.js:68:7)
(node:1582) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:1582) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

解决 了我有太多异步代码运行同步。

const { Builder } = require('selenium-webdriver');
const Firefox = require('selenium-webdriver/firefox');
require('geckodriver');
const serverUri = "http://localhost:3000/#";
let browser;

async function main() {
    const builder = new Builder().forBrowser('firefox');
    builder.setFirefoxOptions(new Firefox.Options().headless());

    browser = await builder.build();
    await browser.get(serverUri);

    try {
        const title = await browser.getTitle();
        console.log(title);
    } catch (ex) {
        console.log("Something went wrong", ex.message);
    } finally {
        await browser.quit();
    }

}

main().catch(console.error);

标签： javascriptreactjsselenium-webdrivermocha.js