jest-circus

What is jest-circus?

The jest-circus package is a test runner for Jest that aims to be a foundation for building testing frameworks. It provides a feature-rich API for defining tests, handling test execution, and setting up and tearing down test environments. It's designed to be more extensible and maintainable than Jest's default test runner.

What are jest-circus's main functionalities?

Defining Tests

This feature allows you to define individual test cases using the `test` function. The code sample demonstrates a simple test that checks if the addition of 1 and 2 equals 3.

test('adds 1 + 2 to equal 3', () => {
  expect(1 + 2).toBe(3);
});

Setup and Teardown

Jest-circus provides lifecycle methods like `beforeEach` and `afterEach` for setting up and tearing down your test environment before and after each test, respectively.

beforeEach(() => {
  initializeCityDatabase();
});

afterEach(() => {
  clearCityDatabase();
});

Test Suites

Organize tests into test suites using the `describe` block. This allows grouping of related tests, making tests easier to manage and understand.

describe('matching cities to foods', () => {
  test('Vienna <3 sausage', () => {
    expect(matchCityToFood('Vienna')).toBe('sausage');
  });
});

Asynchronous Testing

Support for testing asynchronous code using async/await syntax or promises, allowing for straightforward testing of asynchronous operations.

test('the data is peanut butter', async () => {
  await expect(fetchData()).resolves.toBe('peanut butter');
});

Other packages similar to jest-circus

mocha

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple. It's similar to jest-circus in providing a flexible and extensible testing framework, but differs in its execution model and default assertion library integration.

jasmine

Jasmine is a behavior-driven development framework for testing JavaScript code. It does not require a DOM, and it has a clean, obvious syntax so that you can easily write tests. Jasmine is similar to jest-circus in its syntax and approach to defining tests but operates independently of Jest and has its own assertion library.

ava

AVA is a test runner for Node.js with a concise API, detailed error output, and process isolation that lets you develop with confidence. It's similar to jest-circus in its focus on modern JavaScript features and concurrency but differs in its minimalistic approach and focus on speed.

README

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