Playwright's expect.toBeVisible Not Working: A Common Problem Solved
Problem: You're writing a Playwright test, and the expect.toBeVisible assertion is failing, even though the element you're targeting should be visible on the page.
Rephrasing: You're trying to check if a specific element is on the screen in your Playwright test, but your test is failing even though the element is definitely there.
Scenario: Let's imagine you're testing a website with a "Sign Up" button. You've created a Playwright test to ensure this button is visible on the page.
import { test, expect } from '@playwright/test';
test('Sign Up button is visible', async ({ page }) => {
await page.goto('https://www.example.com');
await expect(page.locator('button[data-testid="signup-button"]')).toBeVisible();
});
However, the test fails with an error message similar to:
Error: expect(locator('button[data-testid="signup-button"]')).toBeVisible()
Expected: to be visible
Received: to be hidden
Analysis and Clarification: This issue often arises because of timing discrepancies. Playwright might be trying to check for visibility before the element has fully rendered and become visible on the page. This is especially common when dealing with elements that are:
- Dynamically loaded: Elements that appear after an initial page load, like those loaded via JavaScript or AJAX requests.
- Hidden by default: Elements that are initially hidden using CSS and later made visible through user interaction or other events.
- Behind other elements: The element might be hidden because it's positioned beneath other elements that overlap it.
Solutions:
-
Introduce a
waitFororwaitForSelector:This allows Playwright to wait for the element to be visible on the page before running your assertion.
await page.waitForSelector('button[data-testid="signup-button"]', { state: 'visible' }); await expect(page.locator('button[data-testid="signup-button"]')).toBeVisible(); -
Use the
timeoutoption:Increase the timeout for the
toBeVisibleassertion. This provides more time for the element to become visible.await expect(page.locator('button[data-testid="signup-button"]')).toBeVisible({ timeout: 10000 }); -
Implement explicit waiting:
Use Playwright's
page.waitForFunctionto wait for a specific condition to be met, such as the element's visibility or a particular state change. This offers more control over the waiting mechanism.await page.waitForFunction(() => { return document.querySelector('button[data-testid="signup-button"]').style.display !== 'none'; }); await expect(page.locator('button[data-testid="signup-button"]')).toBeVisible(); -
Inspect element properties:
Use the browser's developer tools to examine the element's CSS properties, specifically its
display,visibility, andopacityvalues. These properties could be preventing the element from being visible. -
Consider the context:
Think about the context of your test. Is the element supposed to be visible immediately after page load, or does it become visible after an action, such as a click event? Adjust your test accordingly to ensure you're checking for visibility at the right time.
Example:
Imagine a website that has a hidden section that becomes visible after a user clicks a "Show More" button.
test('Hidden section becomes visible after clicking "Show More"', async ({ page }) => {
await page.goto('https://www.example.com');
// Wait for the "Show More" button to be visible
await page.waitForSelector('button[data-testid="show-more-button"]', { state: 'visible' });
// Click the "Show More" button
await page.click('button[data-testid="show-more-button"]');
// Wait for the hidden section to become visible
await page.waitForSelector('div[data-testid="hidden-section"]', { state: 'visible' });
// Assert that the hidden section is now visible
await expect(page.locator('div[data-testid="hidden-section"]')).toBeVisible();
});
Conclusion:
Playwright's expect.toBeVisible assertion is a powerful tool for testing the visibility of elements. However, understanding the intricacies of dynamic loading, CSS properties, and timing is crucial for overcoming common pitfalls. By implementing the solutions outlined above, you can ensure your tests accurately reflect the expected behavior of your web application.
Resources:
