How to use checkForCommonEnvironmentErrors method in Jest

Best JavaScript code snippet using jest


Source:index.js Github


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...112 renderedCallsite = `\n${renderedCallsite}\n`;113 return renderedCallsite;114};115const blankStringRegexp = /^\s*$/;116function checkForCommonEnvironmentErrors(error) {117 if (118 error.includes('ReferenceError: document is not defined') ||119 error.includes('ReferenceError: window is not defined') ||120 error.includes('ReferenceError: navigator is not defined')121 ) {122 return warnAboutWrongTestEnvironment(error, 'jsdom');123 } else if (error.includes('.unref is not a function')) {124 return warnAboutWrongTestEnvironment(error, 'node');125 }126 return error;127}128function warnAboutWrongTestEnvironment(error, env) {129 return (130 `The error below may be caused by using the wrong test environment, see ${_chalk.default.dim.underline(132 ''133 )}.\nConsider using the "${env}" test environment.\n\n`134 ) + error135 );136} // ExecError is an error thrown outside of the test suite (not inside an `it` or137// `before/after each` hooks). If it's thrown, none of the tests in the file138// are executed.139const formatExecError = (error, config, options, testPath, reuseMessage) => {140 if (!error || typeof error === 'number') {141 error = new Error(`Expected an Error, but "${String(error)}" was thrown`);142 error.stack = '';143 }144 let message, stack;145 if (typeof error === 'string' || !error) {146 error || (error = 'EMPTY ERROR');147 message = '';148 stack = error;149 } else {150 message = error.message;151 stack =152 typeof error.stack === 'string'153 ? error.stack154 : `thrown: ${(0, _prettyFormat.default)(error, {155 maxDepth: 3156 })}`;157 }158 const separated = separateMessageFromStack(stack || '');159 stack = separated.stack;160 if (separated.message.includes(trim(message))) {161 // Often stack trace already contains the duplicate of the message162 message = separated.message;163 }164 message = checkForCommonEnvironmentErrors(message);165 message = indentAllLines(message, MESSAGE_INDENT);166 stack =167 stack && !options.noStackTrace168 ? '\n' + formatStackTrace(stack, config, options, testPath)169 : '';170 if (171 typeof stack !== 'string' ||172 (blankStringRegexp.test(message) && blankStringRegexp.test(stack))173 ) {174 // this can happen if an empty object is thrown.175 message = `thrown: ${(0, _prettyFormat.default)(error, {176 maxDepth: 3177 })}`;178 }...

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Jest Testing Tutorial

LambdaTest’s Jest Testing Tutorial covers step-by-step guides around Jest with code examples to help you be proficient with the Jest framework. The Jest tutorial has chapters to help you learn right from the basics of Jest framework to code-based tutorials around testing react apps with Jest, perform snapshot testing, import ES modules and more.


  1. What is Jest Framework
  2. Advantages of Jest - Jest has 3,898,000 GitHub repositories, as mentioned on its official website. Learn what makes Jest special and why Jest has gained popularity among the testing and developer community.
  3. Jest Installation - All the prerequisites and set up steps needed to help you start Jest automation testing.
  4. Using Jest with NodeJS Project - Learn how to leverage Jest framework to automate testing using a NodeJS Project.
  5. Writing First Test for Jest Framework - Get started with code-based tutorial to help you write and execute your first Jest framework testing script.
  6. Jest Vocabulary - Learn the industry renowned and official jargons of the Jest framework by digging deep into the Jest vocabulary.
  7. Unit Testing with Jest - Step-by-step tutorial to help you execute unit testing with Jest framework.
  8. Jest Basics - Learn about the most pivotal and basic features which makes Jest special.
  9. Jest Parameterized Tests - Avoid code duplication and fasten automation testing with Jest using parameterized tests. Parameterization allows you to trigger the same test scenario over different test configurations by incorporating parameters.
  10. Jest Matchers - Enforce assertions better with the help of matchers. Matchers help you compare the actual output with the expected one. Here is an example to see if the object is acquired from the correct class or not. -

|<p>it('check_object_of_Car', () => {</p><p> expect(newCar()).toBeInstanceOf(Car);</p><p> });</p>| | :- |

  1. Jest Hooks: Setup and Teardown - Learn how to set up conditions which needs to be followed by the test execution and incorporate a tear down function to free resources after the execution is complete.
  2. Jest Code Coverage - Unsure there is no code left unchecked in your application. Jest gives a specific flag called --coverage to help you generate code coverage.
  3. HTML Report Generation - Learn how to create a comprehensive HTML report based on your Jest test execution.
  4. Testing React app using Jest Framework - Learn how to test your react web-application with Jest framework in this detailed Jest tutorial.
  5. Test using LambdaTest cloud Selenium Grid - Run your Jest testing script over LambdaTest cloud-based platform and leverage parallel testing to help trim down your test execution time.
  6. Snapshot Testing for React Front Ends - Capture screenshots of your react based web-application and compare them automatically for visual anomalies with the help of Jest tutorial.
  7. Bonus: Import ES modules with Jest - ES modules are also known as ECMAScript modules. Learn how to best use them by importing in your Jest testing scripts.
  8. Jest vs Mocha vs Jasmine - Learn the key differences between the most popular JavaScript-based testing frameworks i.e. Jest, Mocha, and Jasmine.
  9. Jest FAQs(Frequently Asked Questions) - Explore the most commonly asked questions around Jest framework, with their answers.

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