Playwright Python Test Generation Instructions

Test Writing Guidelines

Code Quality Standards

  • Locators: Prioritize user-facing, role-based locators (get_by_role, get_by_label, get_by_text) for resilience and accessibility.
  • Assertions: Use auto-retrying web-first assertions via the expect API (e.g., expect(page).to_have_title(…)). Avoid expect(locator).to_be_visible() unless specifically testing for a change in an element’s visibility, as more specific assertions are generally more reliable.
  • Timeouts: Rely on Playwright’s built-in auto-waiting mechanisms. Avoid hard-coded waits or increased default timeouts.
  • Clarity: Use descriptive test titles (e.g., def test_navigation_link_works():) that clearly state their intent. Add comments only to explain complex logic, not to describe simple actions like “click a button.”

Test Structure

  • Imports: Every test file should begin with from playwright.sync_api import Page, expect.
  • Fixtures: Use the page: Page fixture as an argument in your test functions to interact with the browser page.
  • Setup: Place navigation steps like page.goto() at the beginning of each test function. For setup actions shared across multiple tests, use standard Pytest fixtures.

File Organization

  • Location: Store test files in a dedicated tests/ directory or follow the existing project structure.
  • Naming: Test files must follow the test_.py naming convention to be discovered by Pytest.
  • Scope: Aim for one test file per major application feature or page.

Assertion Best Practices

  • Element Counts: Use expect(locator).to_have_count() to assert the number of elements found by a locator.
  • Text Content: Use expect(locator).to_have_text() for exact text matches and expect(locator).to_contain_text() for partial matches.
  • Navigation: Use expect(page).to_have_url() to verify the page URL.
  • Assertion Style: Prefer expect over assert for more reliable UI tests.

Example 

import re
import pytest
from playwright.sync_api import Page, expect

@pytest.fixture(scope="function", autouse=True)
def before_each_after_each(page: Page):
    # Go to the starting url before each test.
    page.goto("https://playwright.dev/")

def test_main_navigation(page: Page):
    expect(page).to_have_url("https://playwright.dev/")

def test_has_title(page: Page):
    # Expect a title "to contain" a substring.
    expect(page).to_have_title(re.compile("Playwright"))

def test_get_started_link(page: Page):
    page.get_by_role("link", name="Get started").click()
    
    # Expects page to have a heading with the name of Installation.
    expect(page.get_by_role("heading", name="Installation")).to_be_visible()

Test Execution Strategy

  1. Execution: Tests are run from the terminal using the pytest command.
  2. Debug Failures: Analyze test failures and identify root causes