Leveraging Code Reusability in Cypress with Custom Commands

Code reusability is a fundamental principle in software development that promotes efficiency and maintainability. In the context of Cypress testing, reusing code reduces redundancy, minimizes errors, and enhances the scalability of test suites. By encapsulating common actions and assertions into reusable functions, testers can save time and effort while ensuring consistency across tests.

Introducing Custom Commands: Cypress allows developers to define custom commands using the Cypress.Commands.add() method. These commands encapsulate sequences of actions or assertions, abstracting away implementation details and promoting a higher level of abstraction in test scripts. Custom commands are defined once and can be reused across multiple test files, promoting modularization and code maintainability.

Creating Custom Commands: Let’s illustrate the process of creating custom commands in Cypress with some practical examples.

1. Custom Command for login: Suppose we frequently need to log in to our application before performing various test scenarios. Instead of repeating the login code in every test, we can create a custom command to handle authentication:

// cypress/support/commands.js

Cypress.Commands.add('login', (username, password) => {
  cy.visit('/login')
  cy.get('#username').type(username)
  cy.get('#password').type(password)
  cy.get('form').submit()
})        

With this custom command in place, logging in becomes as simple as invoking cy.login('username', 'password') in any test file.

2. Custom Command for Checking Page URL: Suppose we frequently need to verify the URL of a page in our tests. We can create a custom command to encapsulate this verification

// cypress/support/commands.js

Cypress.Commands.add('checkPageUrl', (expectedUrl) => {
  cy.url().should('eq', expectedUrl);
})        

Now, we can easily check the URL of a page by invoking cy.checkPageUrl(expectedUrl) in our test scripts.

3. Custom Command for Selecting Dropdown Option: If our application contains dropdown menus that we often interact with, we can create a custom command to select options from them:

// cypress/support/commands.js

Cypress.Commands.add('selectDropdownOption', (dropdownSelector, optionText) => {
  cy.get(dropdownSelector).select(optionText);
})        

This custom command simplifies the process of selecting dropdown options and promotes reusability across tests.

4. Custom Command for Verifying Element Visibility: In scenarios where we frequently need to check if an element is visible on the page, we can create a custom command for this purpose:

// cypress/support/commands.js

Cypress.Commands.add('checkElementVisibility', (elementSelector) => {
  cy.get(elementSelector).should('be.visible');
})        

Now, we can easily verify the visibility of elements by using cy.checkElementVisibility(elementSelector) in our test scripts.

5. Custom Command for Performing Authentication with OAuth: For applications that use OAuth for authentication, we can create a custom command to streamline the login process:

// cypress/support/commands.js

Cypress.Commands.add('loginWithOAuth', () => {
  // Code to perform OAuth login
})        

This custom command abstracts away the complexities of OAuth authentication, making our test scripts cleaner and more maintainable.

Advantages of Custom Commands:

1. Improved Readability: Custom commands abstract away complex interactions, making test scripts more readable and understandable.
2. Enhanced Maintainability: Changes to common actions or assertions can be made in one central location, propagating the updates to all tests that use the custom command.
3. Reusability: Custom commands can be reused across multiple test files, reducing duplication of code and promoting a modular testing approach.
4. Encapsulation: Implementation details are encapsulated within custom commands, promoting a higher level of abstraction and reducing code coupling.

Best Practices for Using Custom Commands:

1. Keep Commands Focused: Each custom command should encapsulate a single action or assertion, keeping them focused and easy to understand.
2. Use Descriptive Names: Choose descriptive names for custom commands that accurately reflect their purpose and functionality.
3. Parameterize when Necessary: When creating custom commands, consider parameterizing inputs to make them more flexible and reusable across different scenarios.
4. Regular Maintenance: Periodically review and refactor custom commands to ensure they remain relevant and efficient as the application evolves.

Conclusion: Code reusability is a cornerstone of efficient and maintainable testing in Cypress. By leveraging custom commands, testers can encapsulate common actions and assertions, promoting readability, maintainability, and scalability of test suites. Incorporating custom commands into your Cypress testing workflow empowers teams to write more expressive, modular, and robust tests, ultimately leading to higher confidence in the quality of the application under test.