Automated testing has become a cornerstone of modern web development, ensuring that applications behave as expected. Among the many tools available for this purpose, Cypress stands out due to its ease of use, powerful features, and active community. One of the common challenges faced during web testing is dealing with JavaScript prompt pop-up windows. This article will guide you through the process of handling these prompts in Cypress.

Understanding JavaScript Prompts

JavaScript prompts are pop-up boxes that require user interaction. They typically present a message and request input from the user before they can proceed. These prompts can be used for various purposes, such as confirming actions, collecting user input, or displaying important messages.

Why Handle Prompts in Tests?

Handling prompts is crucial when automating tests, especially end-to-end tests because they can block the execution flow. If a prompt appears and the test script does not handle it, it will wait indefinitely, leading to a timeout and test failure. Therefore, it’s essential to have strategies in place to manage these pop-ups effectively.

Cypress and Prompt Handling

Cypress, with its modern architecture and comprehensive API, provides several methods to handle JavaScript prompts. Here’s a step-by-step guide to managing prompt pop-up windows using Cypress:

Step 1: Setting Up Cypress

First, ensure that you have Cypress installed and set up in your project. If not, you can install it using npm:

npm install cypress –save -dev

After installation, open Cypress by running:

npx cypress open

Step 2: Writing a Test Case

Let’s consider a simple example where a prompt appears when a button is clicked. Here’s the HTML snippet:

<button onclick="showPrompt()">Click me</button>

<script>
  function showPrompt() {
    var person = prompt("Please enter your name:", "Harry Potter");
    if (person != null) {
      document.getElementById("demo").innerHTML =
        "Hello " + person + "! How are you today?";
    }
  }
</script>

<p id="demo"></p>

To handle this prompt in Cypress, you can use the cy.window() command to stub the prompt method.

Step 3: Stubbing the Prompt Method

Cypress allows you to stub browser methods using cy.stub(). Here’s how you can stub the prompt method:

describe('Prompt Handling Test', () => {
  it('handles prompt pop-up', () => {
    cy.visit('path/to/your/page.html'); // Adjust the path as necessary

    cy.window().then((win) => {
      cy.stub(win, 'prompt').returns('John Doe');
    });

    cy.get('button').click();

    cy.get('#demo').should('contain', 'Hello John Doe! How are you today?');
  });
});

In this example, when the button is clicked, the stubbed prompt method returns ‘John Doe’ instead of displaying the actual prompt. This allows the test to proceed without interruption.

Result:

Result of prompt method stub

Best Practices for Handling Prompts

• Stub Methods Appropriately: Ensure that you stub the prompt method before the action that triggers it. This prevents the actual prompt from appearing.
• Test Different Scenarios: Consider testing various inputs and edge cases to ensure comprehensive coverage.
• Clean Up Stubs: Cypress automatically resets stubs and spies between tests, but it’s good practice to be aware of this and ensure no lingering side effects.

Conclusion

Handling JavaScript prompts in Cypress is straightforward and can significantly enhance the robustness of your test suite. By stubbing the prompt method, you can automate interactions with these pop-ups, ensuring smooth and uninterrupted test execution. With Cypress, managing such scenarios becomes a seamless part of your testing workflow, allowing you to focus on building and delivering high-quality web applications.