The field of website testing has now reached a point of stability. Several testing tools have received overwhelmingly excellent user feedback, well-known testing best practices have arisen, and testing has become a more fundamental component of web developers’ jobs.
Cutting-edge internet testing tools are quick, insightful, and simple to use. These tools will make testing and development a lot more fun for you.
Generally testing can be divided into several categories such as:
Unit testing where individual units, such as functions or classes, are tested by providing input and ensuring that the result is as expected.
expect(fn(90)).to.be(10)
Integration testing is done to across multiple units to check if their purpose is achieved and check their flaws too.
End to end tests or commonly known as functional testing it involves controlling the browser programmatically allowing you to test user scenarios on the browser itself. These tests typically ignore an application’s internals and examine it as if it were a black box.
Why write Unit Tests?
When I ask developers if they built tests for their software, they constantly say, “I didn’t have time for them” or “I don’t need them; I know it works.”
Write of test cases make the developer confident that their code actually works and there is assurance that the application will not break in production. When a developer unit testing in mind it helps them achieve better architectural decisions in their application through the separation of concerns
Testing tools.
Testing is accomplished by use of several testing tools that can be categorized depending on their functionalities
· Test launchers which help in launch of your tests in the node terminal or on the test browser example (Karma, Jasmine, Jest, TestCafe, Cypress, webdriverio)
· Testing frameworks help you to arrange your tests in a readable and scalable way. (Mocha, Jasmine, Jest, Cucumber, TestCafe, Cypress)
· Assertion functions are used to check if a test returns what you expect it to return and otherwise, to throw a clear exception. (Chai, Jasmine, Jest, Unexpected, TestCafe, Cypress)
· Mocks, spies, and stubs to simulate tests scenarios, isolate the tested part of the software from other parts, and attach to processes to test certain aspects of a scenario. (Sinon, Jasmine, enzyme, Jest, testdouble)
· Browser Controllers simulate user actions for E2E Tests. (Nightwatch, Nightmare, Phantom, Puppeteer, TestCafe, Cypress)
How to Write Your First JavaScript Unit Test
Example in jest testing framework
Install jest
npm i jest — save-dev
Write the script that requires testing and save it as index.js
Write the testing script named as <filename>.test.js for my case index.test.js:
Configure the package. json as follows
“scripts”: {
“test”: “jest”
}
To test run
npm run test
Running tests
Running tests in the browser which involves by creating an HTML page with the test libraries and test files included as JS scripts.
Tests can be done in a headless browser, which is a method of launching browsers in a specific mode that prevents them from rendering the user interface on the screen. This allows you to run them much more quickly in terms of performance, and even completely from the command line.
Tests can also be conducted in Node.js by simply importing the test files, which would import the files being tested, which would normally run in the browser.