Unit testing and end-to-end testing in front-end development

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Today’s content:Unit testing and end-to-end testing in front-end development

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Unit Testing and End-to-End Testing in front-end development

Unit Testing

1. definition:

   • Unit testing is the process of testing the smallest testable unit in the software. In front-end development, it is usually tested whether independent units such as functions, components, and modules in the application behave as expected.

2. Target:

   • Verify unit correctness: Make sure the functionality and logic of each unit is correct.
   • Improving code quality: Unit testing helps discover and correct potential problems and improves the maintainability and scalability of the code.

3. Tools and frameworks:

   • Jest: A JavaScript testing framework developed by Facebook, used for testing React applications, etc.
   • Mocha: A universal JavaScript testing framework that supports multiple assertion libraries.
   • Jasmine: Behavior-driven development (BDD) testing framework for JavaScript.

4. Example code (using Jest):

   // 要测试的函数
   function add(a, b) {
         
         
     return a + b;
   }
   
   // 对应的测试代码
   test('adds 1 + 2 to equal 3', () => {
         
         
     expect(add(1, 2)).toBe(3);
   });
   

End-to-End Testing

1. definition:

   • End-to-end testing is the process of testing the functionality and flow of the entire application. It simulates the actual actions performed by the user in the application and checks whether the application is working as expected.

2. Target:

   • Verify the functionality of the entire application: Ensure proper integration and interaction between different components and modules.
   • Simulate user behavior: Simulate the interaction between the user and the application and check whether the user path is correct.

3. Tools and frameworks:

   • Cypress: A modern JavaScript end-to-end testing framework that provides real-time reloading, automatic waiting and other functions.
   • Puppeteer: The Node library provided by Google is used to control the browser for end-to-end testing.
   • Protractor: An end-to-end testing tool designed specifically for Angular applications.

4. Example code (using Cypress):

   // 示例测试代码
   describe('My First Test', () => {
         
         
     it('Does not do much!', () => {
         
         
       // Visit a web page
       cy.visit('https://example.cypress.io');
   
       // Interact with elements on the page
       cy.get('.navbar-nav').contains('Commands').click();
   
       // Make assertions
       cy.url().should('include', '/commands/actions');
       cy.get('.action-email').should('be.visible');
     });
   });
   

Summary of differences

• unit test:

  • Test the smallest testable unit, such as functions and components.
  • Pay attention to whether the unit behaves as expected.
  • More fine-grained, suitable for testing business logic, pure functions, etc.

• End-to-end testing:

  • Test the entire application, simulating actual user operations.
  • Pay attention to whether the functions and processes of the entire application are normal.
  • More coarse-grained, suitable for testing user paths, interactions, etc.

In actual projects, unit testing and end-to-end testing are often used in combination to ensure the quality and stability of the application at different levels.

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