How to use buildHintString method in Jest

Best JavaScript code snippet using jest

formatNodeAssertErrors.js

Source: formatNodeAssertErrors.js Github

copy

Full Screen

...120 .replace(message, '')121 .replace(/​AssertionError(.*)/​g, '');122 if (operatorName === 'doesNotThrow') {123 return (124 buildHintString(assertThrowingMatcherHint(operatorName)) +125 _chalk.default.reset(`Expected the function not to throw an error.\n`) +126 _chalk.default.reset(`Instead, it threw:\n`) +127 ` ${(0, _jestMatcherUtils.printReceived)(actual)}` +128 _chalk.default.reset(129 hasCustomMessage ? '\n\nMessage:\n ' + message : ''130 ) +131 trimmedStack132 );133 }134 if (operatorName === 'throws') {135 return (136 buildHintString(assertThrowingMatcherHint(operatorName)) +137 _chalk.default.reset(`Expected the function to throw an error.\n`) +138 _chalk.default.reset(`But it didn't throw anything.`) +139 _chalk.default.reset(140 hasCustomMessage ? '\n\nMessage:\n ' + message : ''141 ) +142 trimmedStack143 );144 }145 if (operatorName === 'fail') {146 return (147 buildHintString(assertMatcherHint(operator, operatorName, expected)) +148 _chalk.default.reset(hasCustomMessage ? 'Message:\n ' + message : '') +149 trimmedStack150 );151 }152 return (153 buildHintString(assertMatcherHint(operator, operatorName, expected)) +154 _chalk.default.reset(`Expected value ${operatorMessage(operator)}`) +155 ` ${(0, _jestMatcherUtils.printExpected)(expected)}\n` +156 _chalk.default.reset(`Received:\n`) +157 ` ${(0, _jestMatcherUtils.printReceived)(actual)}` +158 _chalk.default.reset(hasCustomMessage ? '\n\nMessage:\n ' + message : '') +159 (diffString ? `\n\nDifference:\n\n${diffString}` : '') +160 trimmedStack161 );162}163function isAssertionError(error) {164 return (165 error &&166 (error instanceof _assert.AssertionError ||167 error.name === _assert.AssertionError.name ||168 error.code === 'ERR_ASSERTION')169 );170}171function buildHintString(hint) {172 return hint ? hint + '\n\n' : '';173}174var _default = formatNodeAssertErrors;...

Full Screen

Full Screen

assertionErrorMessage.js

Source: assertionErrorMessage.js Github

copy

Full Screen

...87 .replace(message, '')88 .replace(/​AssertionError(.*)/​g, '');89 if (operatorName === 'doesNotThrow') {90 return (91 buildHintString(assertThrowingMatcherHint(operatorName)) +92 _chalk.default.reset(`Expected the function not to throw an error.\n`) +93 _chalk.default.reset(`Instead, it threw:\n`) +94 ` ${(0, _jestMatcherUtils.printReceived)(actual)}` +95 _chalk.default.reset(96 hasCustomMessage ? '\n\nMessage:\n ' + message : ''97 ) +98 trimmedStack99 );100 }101 if (operatorName === 'throws') {102 return (103 buildHintString(assertThrowingMatcherHint(operatorName)) +104 _chalk.default.reset(`Expected the function to throw an error.\n`) +105 _chalk.default.reset(`But it didn't throw anything.`) +106 _chalk.default.reset(107 hasCustomMessage ? '\n\nMessage:\n ' + message : ''108 ) +109 trimmedStack110 );111 }112 if (operatorName === 'fail') {113 return (114 buildHintString(assertMatcherHint(operator, operatorName, expected)) +115 _chalk.default.reset(hasCustomMessage ? 'Message:\n ' + message : '') +116 trimmedStack117 );118 }119 return (120 buildHintString(assertMatcherHint(operator, operatorName, expected)) +121 _chalk.default.reset(`Expected value ${operatorMessage(operator)}`) +122 ` ${(0, _jestMatcherUtils.printExpected)(expected)}\n` +123 _chalk.default.reset(`Received:\n`) +124 ` ${(0, _jestMatcherUtils.printReceived)(actual)}` +125 _chalk.default.reset(hasCustomMessage ? '\n\nMessage:\n ' + message : '') +126 (diffString ? `\n\nDifference:\n\n${diffString}` : '') +127 trimmedStack128 );129}130function buildHintString(hint) {131 return hint ? hint + '\n\n' : '';132}133var _default = assertionErrorMessage;...

Full Screen

Full Screen

StackOverFlow community discussions

Questions
Discussion

How to test if a method returns an array of a class in Jest

How do node_modules packages read config files in the project root?

Jest: how to mock console when it is used by a third-party-library?

ERESOLVE unable to resolve dependency tree while installing a pacakge

Testing arguments with toBeCalledWith() in Jest

Is there assertCountEqual equivalent in javascript unittests jest library?

NodeJS: NOT able to set PERCY_TOKEN via package script with start-server-and-test

Jest: How to consume result of jest.genMockFromModule

How To Reset Manual Mocks In Jest

How to move '__mocks__' folder in Jest to /test?

Since Jest tests are runtime tests, they only have access to runtime information. You're trying to use a type, which is compile-time information. TypeScript should already be doing the type aspect of this for you. (More on that in a moment.)

The fact the tests only have access to runtime information has a couple of ramifications:

  • If it's valid for getAll to return an empty array (because there aren't any entities to get), the test cannot tell you whether the array would have had Entity elements in it if it hadn't been empty. All it can tell you is it got an array.

  • In the non-empty case, you have to check every element of the array to see if it's an Entity. You've said Entity is a class, not just a type, so that's possible. I'm not a user of Jest (I should be), but it doesn't seem to have a test specifically for this; it does have toBeTruthy, though, and we can use every to tell us if every element is an Entity:

    it('should return an array of Entity class', async () => {
         const all = await service.getAll()
         expect(all.every(e => e instanceof Entity)).toBeTruthy();
    });
    

    Beware, though, that all calls to every on an empty array return true, so again, that empty array issue raises its head.

If your Jest tests are written in TypeScript, you can improve on that by ensuring TypeScript tests the compile-time type of getAll's return value:

it('should return an array of Entity class', async () => {
    const all: Entity[] = await service.getAll()
    //       ^^^^^^^^^^
    expect(all.every(e => e instanceof Entity)).toBeTruthy();
});

TypeScript will complain about that assignment at compile time if it's not valid, and Jest will complain at runtime if it sees an array containing a non-Entity object.


But jonrsharpe has a good point: This test may not be useful vs. testing for specific values that should be there.

https://stackoverflow.com/questions/71717652/how-to-test-if-a-method-returns-an-array-of-a-class-in-jest

Blogs

Check out the latest blogs from LambdaTest on this topic:

19 Best Practices For Automation testing With Node.js

Node js has become one of the most popular frameworks in JavaScript today. Used by millions of developers, to develop thousands of project, node js is being extensively used. The more you develop, the better the testing you require to have a smooth, seamless application. This article shares the best practices for the testing node.in 2019, to deliver a robust web application or website.

A Comprehensive Guide To Storybook Testing

Storybook offers a clean-room setting for isolating component testing. No matter how complex a component is, stories make it simple to explore it in all of its permutations. Before we discuss the Storybook testing in any browser, let us try and understand the fundamentals related to the Storybook framework and how it simplifies how we build UI components.

Top Automation Testing Trends To Look Out In 2020

Quality Assurance (QA) is at the point of inflection and it is an exciting time to be in the field of QA as advanced digital technologies are influencing QA practices. As per a press release by Gartner, The encouraging part is that IT and automation will play a major role in transformation as the IT industry will spend close to $3.87 trillion in 2020, up from $3.76 trillion in 2019.

How To Speed Up JavaScript Testing With Selenium and WebDriverIO?

This article is a part of our Content Hub. For more in-depth resources, check out our content hub on WebDriverIO Tutorial and Selenium JavaScript Tutorial.

Blueprint for Test Strategy Creation

Having a strategy or plan can be the key to unlocking many successes, this is true to most contexts in life whether that be sport, business, education, and much more. The same is true for any company or organisation that delivers software/application solutions to their end users/customers. If you narrow that down even further from Engineering to Agile and then even to Testing or Quality Engineering, then strategy and planning is key at every level.

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.

Chapters

  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.

Run Jest automation tests on LambdaTest cloud grid

Perform automation testing on 3000+ real desktop and mobile devices online.

Try LambdaTest Now !!

Get 100 minutes of automation test minutes FREE!!

Next-Gen App & Browser Testing Cloud

Was this article helpful?

Helpful

NotHelpful