What is Jest Framework?
It is a well-defined document and requires little configuration, and can be extended whenever required to match out your requirements. Jest makes us do testing delightfully.
It is very fast and safe; Jest can run all your tests parallel by ensuring they have a unique global state. To make things quicker and easier, it runs previously failed tests first and then reorganizes the runs of the next tests, which are based on the long test files.
Jest has a great toolkit available to programmers at one place itself, which is very well documented, properly maintained and well arranged in a good manner. It also helps to maximize the performance level by managing the tests in a parallel manner by running them in their processes. Jest also maintained the information coverage records, and from entire projects and various untested files, it collects code coverage information.
With the help of various mock functions API ( Application Programming Interface ), we can use mocked imports to observe various function calls with the easily readable syntax of any text.
Jest is very popular for unit testing and can be easily extended to include various integration tests. On the scale of different unit tests, automated tests are extremely contrary to end-to-end testing. There is too much software testing, which verifies different aspects of any mobile or web application, each operating on a different coating or layer and providing their unique type of feedback.
Unit testing is frequently cited as the most important among various types of software testing automated testing. Unit tests are mainly used to verify your application by breaking it into small parts in complete isolation. Also, unit tests ensure to provide more than the expected work.
As a result, unit testing is usually -
Hence, unit testing is less realistic or imaginative because users usually do not interact with units under complete isolation.
Features of Jest Framework
From all the above features and advantages of the jest framework, we can conclude that Jest is a very fast testing framework and very convenient and easy for us to install and set up a jest in our system. It is developed by Facebook and actively used by Facebook and many other users to test all the react applications and react based projects. It has convenient and frequently used packages, supports Typescript.
Basic Setup for executing any Test
Whenever we create a web or mobile application, we must test every feature and element of that application and its point of interaction with a user, which is quite mandatory. Web applications are consist of various modules and functions, which is mainly stated as the unit of code, and these units of code also need to be tested.
Two scenarios commonly arise in this situation:
For both the cases mentioned above, one must check whether the given functions produce the desired output.
For every test, there is a predefined flow in which, through following the flow step by step, our code is fully tested after undergoing till the end of the flow.
Jest Installation Process
There are certain prerequisites and installation process of jest framework, which is necessary before writing your first test script with Jest. Such test script can also be a selenium test automation script.
So to run our jest tests scripts, we need to install some important libraries and packages, which is predefined set for to check particular test scripts.
By using the command line as mentioned below, you can install the jest module using npm.
By using the Java - SDK jest keyword, testers will run the commands in the command line. Before further moving for the jest framework installation process, you must check whether your system must have already done with the installation process of Java Development Kit and configure the system with the JAVA environment; this is because Jest is a selenium test framework and selenium which is built on Java itself.
You can install the jest module globally using the flag ' -g ', and also, you can use the ' -g ' flag along with the npm command.
To use various Jest commands directly without setting up the package file for npm tests, you can do it easily by using the ' - g ' flag.
Let us understand more about the jest framework with the help of the example mentioned below-
Jest Example using package.json
If you want more information about test runs, use -verbose flag because Jest produces only rudimentary output by default.
If you want to run or execute one on one individual tests in a particular sequence, then you can use the npx jest test name command.
Thus, testers can set up Jest to run various tests of a particular test directory for a specified test.
There are some procedural steps that you are required to follow before executing any test or program: