As a test engineer, you have to use DevTools for efficient testing of UI and frontend, and the browser’s Console is an essential part of it. — Browser DevTools provides invaluable assistance for the functional testing of web services. At a minimum, opened Browser Console will display errors on a testing web page. The topic of this article is the Console’s command line — a tool that allows to evaluate JavaScript inside a browser. This means it…

When the number of tests (test files) for my current work project passed over a hundred, it became interesting to see what kind of assertions are the most frequently used. — Introductory notes about the testing project: My testing project is a modern client-server application. Backend (API) is tested separately. Frontend (on React) is full of business logic and has a multimodal interface: Automated tests cover more than 80% of the functionality and are the main component of regression testing.

Sometimes, as a test engineer, you wish to execute unintended scripts in your autotests to set preconditions or check unusual functionality. — Playwright page.evaluate() method allows to execute code within the context of a web page. If the function returns a Promise, the evaluate() method will wait for the Promise to resolve before returning. …

The presence of HTTP request realizations makes frontend testing frameworks like Cypress and Playwright suitable tools for API testing as well. — I was very skeptical about testing API with all-in-one frontend testing tools like Cypress and Playwright, but I decided to give it a try. Jest — another popular frontend testing framework — also can be used for API testing, but it should be extended with third-party libraries like Axios, GOT…

Sometimes, as a test engineer, you need to log in to Google (or other third-party authentication providers) to give access to your website for autotests. — In my recent project, I have to test a web app under an authenticated user, but the only authentication provider was Google. The problem with third-party authentication providers for autotests are: Complicated API; Auth providers have anti-robot detectors.

Sometimes, as a test engineer, you have to perform testing under a knotty environment and not affect production with your activity. Autotests can help, but they require thorough preparations. — Before diving into the topic about autotests, I need to explain the architecture of my project and its testing environments. Without this context, it will be unclear what a problem is solved here: I have a cluster of hundreds of IoT devices;

As a test engineer who has to maintain a bunch of autotests, you will definitely face the task of speeding up the execution of your test suite. — When your autotests grow in number, they are running slower and slower. Managers and developers do not usually like to wait long to find out the results of regression testing. To shorten the feedback loop, your test suite should run as fast as possible (within reason).

Being a test engineer (QA) for a decade «I’ve seen things you people wouldn’t believe», I’ve tested enough web applications to accumulate experience that can be shared. I collected tricky test cases which somehow led to bugs and hacks to perform unusual checks. They are sorted by logical blocks in…

When a frontend team starts building a testing infrastructure, there is always a debate about the choice of testing tools. — There are dozens of tools for testing web applications on JavaScript, TypeScript and Node.js. Ava — test runner; CodeceptJS — end-to-end testing framework; Cypress — end-to-end browser testing framework; Hermione — test runner for browser testing based on Mocha and WebdriverIO;

While working on test automation in different projects, I’ve learned that there are not enough static analyzers and code formatters for writing good tests. The team had to have an agreement on how the tests should be written. — If any team member will write tests with his own ideal vision it will be a mess. Some patterns, applicable to unit tests on Java or Python, do not fit for integration tests on JavaScript and vice versa. …

The main tools for writing UI tests are: browser, IDE, and testing framework documentation. — Playwright’s documentation is rich and intricate at the same time. Sometimes, you can make a check or perform an action one way, and after a while, find that it could be done in another way — just because you look into the API section instead of Docs or vice versa. …

Testing JSON could be a part of contract testing — you check whether the response body corresponds to specification (or contract or terms of reference). — The most appropriate way to do that is through JSON Schema — the method of description of the structure of the JSON data. Besides JSON Schema, each individual key/value pair can be checked for compliance with a number of criteria from the specification.

Sometimes, as a test engineer, you have to deal with advanced technology, such as WebSockets position itself. — If you have ever tested HTTP API, then you will not encounter very difficulties with testing bidirectional messages. But there are a few features inherent in WebSockets which should be taken into account before starting testing. Theory A WebSocket is a persistent connection between client and server. WebSockets provide a full-duplex…

As a test engineer, I have been using WebdriverIO with Selenium WebDriver for frontend automation for a few years. — Recently I got an opportunity to move away from Selenium and therefore had to compare alternatives (inside my usual stack of TypeScript and Node.js): Cypress, as the most hyped automation tool; Playwright, as a more high-level tool close to the browser. Puppeteer did not hit my shortlist because it is…

As a web application test engineer, you need to test backend (APIs) as easy as frontend (UI in a browser). — Dozens of articles appear every year that tell about «the best tools for API testing» including Swagger (which is a tool for documentation and should be implemented by developers), REST Assured (which is a DSL for Java projects and requires programming skills), JMeter (which is a tool for load testing)…

The DevTools «Network» tab provides almost everything for API testing — from checking responses to making requests. — As a web application test engineer, you need to test integration of backend (APIs) with frontend (UI in a browser). During this activity the DevTools «Network» tab should be opened as a «must have» tool, because of the features described below: Network Activity Request Details Advanced Filters

Sometimes, as a test engineer, you need to perform a full-scale check of your web application for vulnerabilities. — Web application security testing is not the topic of one article, it takes a whole book. So I will focus only on the example of scanning for XSS (cross-site scripting) with one special tool — Burp Suite. You can try to find XSS vulnerabilities manually, but it won’t be productive…

Sometimes, as a test engineer, you need to check that your web application is not vulnerable. — I am not going to describe what security testing is, because there are many introductory articles about it. …

There are not many good books about software testing compared to other areas of software development (programming, management or design). But the knowledge that can be applied to testing can be learned from other sources. I have collected a list of non-technical (almost) books which can be recommended for QA…

Sometimes, as a test engineer, you need to perform a non-function testing — When developers start to speed up an API the QA department usually get two types of tasks: Сheck that handlers work the same way as they worked before (that could be tested by comparison of responses); Check that handlers start work faster. «Start work faster» means starting to respond in…