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Jest code coverage generation examples

April 28, 2023 ·  4 min read

This tutorial explains about following things Jest Code Coverage report Jest find uncovered code Jest code coverage generates html, info, and json format Jest code coverage for Single file Code Coverage is an important metric for code quality, It is a percentage of code-written test cases. How to Generate Code Coverage Report This tutorial does not talks about how to add jest to node projects. Jest CLI provides a --coverage option to generate code coverage for javascript files in a project....

Jest How to skip single or suite of tests with examples

April 28, 2023 ·  4 min read

This tutorial explains how to skip unit tests in Jest Framework. How to skip a single test in jest How to skip test suite in a jest Jest it only tests example Jest cli to ignore test files How to skip single test cases in Jest First, Let’s write a sample of 5 tests for one suite. describe is used to write a group of tests called Test Suite. test and it uses to write a single test case....

Jest How to test modules and single functions with examples

April 27, 2023 ·  1 min read

Jest is a testing framework to test different javascript components. This tutorial explains how to test and mock entire modules and single functions First, let’s define a single function add.js export const add = (a,b) => a+b; Let’s define a Module import { add } from './add' export const sum = (a,b) => add(a+b); How to Mock entire modules in javascript using Jest the calculator is a module that calls other named functions from other files....

2 ways to print Jest console debug logs with examples

April 26, 2023 ·  2 min read

Sometimes, it is very difficult to debug test case execution for fixing failed test cases in JEST. I faced console.log not working for printing debug logs. console.log outputs nothing during test case execution Jest prints log using console.log statements There are two options to enable logging using –silent Jest by default suppresses the console log statements. It shows nothing instead of printing a log message. JEST provides CLI option --silent=false to enable print log messages....

Jest cache - Disable, Find Cache Directory with examples

April 26, 2023 ·  2 min read

This tutorial explains about below things jest cache allows you to run the test cases faster to improve the execution time. Jest provides multiple options to run in any javascript projects jest command line. How to disable cache in jest test cases the jest command line provides two options to enable or disable the cache --cache: Enable the cache, It is a default option. --no-cache: Disable the cache jest --cache jest by default store its in a temporary cache for performance improvement...

How to run jest multiple or single file or test blocks with examples

April 23, 2023 ·  2 min read

This tutorial explains how to run jest tests with an example Jest is a testing framework to write unit tests in javascript applications. Running all test files in a javascript using jest framework Jest test files can be executed using the npm command or jest cli command line execution. using npm command, First, define commands in package.json { "scripts": { "test": "jest" } } you can use the npm run test or npm test command to execute all tests....