As a software tester, I have had my fair share of struggles dealing with asynchronous behaviour while testing web applications. And when it comes to testing with Cypress, the experience can be even more challenging. However, with the right approach and techniques, one can Mastering Cypress and handle asynchronous behaviour with ease.In this article, I will explore the ‘cypress then’ command and other Cypress commands that can help you handle asynchronous behaviour. I will also share some best practices and tips to help you become proficient in testing web applications with Cypress.

Introduction to Cypress and asynchronous behaviour #

Mastering Cypress is a popular JavaScript-based end-to-end testing framework that is designed to make testing web applications easier and faster. However, one of the challenges of testing web applications with Cypress is dealing with asynchronous behaviour.

Asynchronous behaviour in web applications is when a task takes time to complete, and the browser has to wait for the task to complete before moving on to the next step. This behaviour can cause issues with test automation as the tests may fail due to the browser not waiting for the task to complete.

Understanding the ‘cypress then’ command #

The ‘cypress then’ command is one of the ways to handle asynchronous behaviour in Cypress. When a Cypress command is executed, it returns a promise, which can be resolved using the ‘cypress then’ command.

The ‘cypress then’ command takes a callback function that is executed once the promise is resolved. The callback function can be used to perform other Cypress commands or assertions.

Here is an example of using the ‘cypress then’ command to handle a login form that takes time to authenticate:

cy.get('#username').type('myusername')cy.get('#password').type('mypassword')cy.get('#login-button').click().then(() => {  // Perform other Cypress commands or assertions})

In this example, the ‘cypress then’ command is used to wait for the login form to authenticate before performing other Cypress commands or assertions.

How to use ‘cypress before’ and ‘cypress before all’ #

The ‘cypress before’ and ‘cypress before all’ commands are used to set up test fixtures before running the tests. These commands can also be used to handle asynchronous behaviour before running the tests.

The ‘cypress before’ command is used to set up a fixture before each test. This command takes a callback function that can be used to set up a fixture.

before(() => {  // Set up a fixture})

The ‘cypress before all’ command is used to set up a fixture once before all the tests are run. This command takes a callback function that can be used to set up a fixture.

before(() => {  // Set up a fixture})

These commands can be used to handle asynchronous behaviour by using the ‘cypress then’ command inside the callback function.

before(() => {  cy.get('/api/data').then((response) => {    // Save the response to a fixture  })})

In this example, the ‘cypress before’ command is used to wait for the API response before saving it to a fixture.

Using ‘cypress promise’ and ‘cypress-promise’ to handle async behaviour #

The ‘cypress promise’ and ‘cypress-promise’ commands are used to handle promises in Cypress. These commands can be used to handle asynchronous behaviour by resolving promises before executing other Cypress commands.

The ‘cypress promise’ command takes a promise and resolves it. This command can be used to resolve promises returned by Cypress commands.

cy.get('/api/data').then(cy.wrap).then((data) => {  // Perform some action with the data})

The ‘cypress-promise’ command is a utility that can be used to handle promises in Cypress. This command can be used to convert a promise to a Cypress promise.

Cypress.Promise.resolve('/api/data').then((response) => {  // Perform some action with the response})

Integrating ‘cypress async/await’ with ‘cypress it’ #

The ‘cypress async/await’ command is a way to handle asynchronous behaviour in Cypress using the async/await syntax. This command can be integrated with the ‘cypress it’ command to write tests that handle asynchronous behaviour with ease.

Here is an example of using the ‘cypress async/await’ command with the ‘cypress it’ command:

it('should load data from the API', async () => {  const response = await cy.request('/api/data')  expect(response.status).to.equal(200)})

In this example, the ‘cypress async/await’ command is used to wait for the API response before performing an assertion.

Techniques for handling asynchronous behaviour in Cypress #

Handling asynchronous behaviour in Cypress can be challenging, but there are some techniques that can make the process easier. Here are some techniques for handling asynchronous behaviour in Cypress:

• Use the ‘cypress then’ command to handle promises returned by Cypress commands
• Use the ‘cypress before’ and ‘cypress before all’ commands to set up test fixtures and handle asynchronous behaviour
• Use the ‘cypress-promise’ command to convert promises to Cypress promises
• Use the ‘cypress async/await’ command to handle asynchronous behaviour using the async/await syntax

Using ‘cypress await’ and ‘cypress after all’ #

The ‘cypress await’ and ‘cypress after all’ commands are used to handle asynchronous behaviour after the tests have finished running.

The ‘cypress await’ command is used to wait for a promise to resolve before continuing with other Cypress commands.

cy.wait(1000).then(() => {  // Perform some action after waiting for 1 second})

The ‘cypress after all’ command is used to clean up test fixtures after all the tests have finished running.

after(() => {  // Clean up test fixtures})

Tips for handling ‘cypress click then’ and other async events #

Handling ‘cypress click then’ and other async events can be challenging as they may not always behave as expected. Here are some tips for handling ‘cypress click then’ and other async events:

• Use the ‘cypress then’ command to handle promises returned by Cypress commands
• Use the ‘cypress-promise’ command to convert promises to Cypress promises
• Use the ‘cypress wait’ command to wait for a specific amount of time before continuing with other Cypress commands

Best practices for working with Cypress and async behaviour #

Here are some best practices for working with Cypress and async behaviour:

• Use the ‘cypress then’ command to handle promises returned by Cypress commands
• Use the ‘cypress before’ and ‘cypress before all’ commands to set up test fixtures and handle asynchronous behaviour
• Use the ‘cypress async/await’ command to handle asynchronous behaviour using the async/await syntax
• Use the ‘cypress-promise’ command to convert promises to Mastering Cypress promises
• Use the ‘cypress wait’ command to wait for a specific amount of time before continuing with other Cypress commands

Conclusion #

Mastering Cypress and understanding asynchronous behaviour is essential for any software tester. By using the right techniques and commands, one can handle asynchronous behaviour with ease.

In this article, I have explored the ‘cypress then’ command and other Cypress commands that can help you handle asynchronous behaviour. I have also shared some best practices and tips to help you become proficient in testing web applications with Cypress.