--- title: Knowledge check | Page Object Model and Framework Design description: Ten questions on the decisions this course made, and why. Each answer comes with a short explanation. 1. A developer renames the login button's id from… source_url: html: https://testingbot.com/resources/courses/page-object-model/knowledge-check md: https://testingbot.com/resources/courses/page-object-model/knowledge-check.md --- Course [Page Object Model and Framework Design](https://testingbot.com/resources/courses/page-object-model) Chapter 10 of 10 1. [1 What Is the Page Object Model?](https://testingbot.com/resources/courses/page-object-model) 2. [2 Your First Page Object in Selenium](https://testingbot.com/resources/courses/page-object-model/first-page-object) 3. [3 Page Object Model in Playwright](https://testingbot.com/resources/courses/page-object-model/playwright-page-objects) 4. [4 Components and Fluent Page Objects](https://testingbot.com/resources/courses/page-object-model/components-and-fluent-pages) 5. [5 Page Factory vs Plain By Locators](https://testingbot.com/resources/courses/page-object-model/page-factory-vs-by-locators) 6. [6 Test Data, Config and Environments](https://testingbot.com/resources/courses/page-object-model/test-data-and-config) 7. [7 Test Automation Framework Structure](https://testingbot.com/resources/courses/page-object-model/framework-layout) 8. [8 Run the Framework in Parallel on a Grid](https://testingbot.com/resources/courses/page-object-model/parallel-on-a-grid) 9. [9 POM Anti-Patterns and When to Skip POM](https://testingbot.com/resources/courses/page-object-model/anti-patterns) 10. [10 Knowledge check](https://testingbot.com/resources/courses/page-object-model/knowledge-check) [Exit course](https://testingbot.com/resources/courses) Chapter 10 of 10 Intermediate 5 min read Updated Nov 2026 # Knowledge check Ten questions on the decisions this course made, and why. Each answer comes with a short explanation. 1. A developer renames the login button's id from `submit` to `login-button`. In a suite built with page objects, what should need to change? Every test that logs in One locator in `LoginPage` The test data files for each environment Locators live in exactly one place, the page object. If tests had to change, locator knowledge has leaked out of the page object layer. 2. On the practice site, `#error` is in the DOM from page load with opacity 0. In Playwright, `await expect(page.locator('#error')).toBeVisible()` right after `goto()` will... Fail, because the element is transparent Time out waiting for the element to appear Pass, because Playwright treats `opacity:0` as visible Playwright's visibility check ignores opacity, so the assertion passes without any login attempt. The page object encodes the real meaning with `#error.show`. Selenium's `isDisplayed()` returns false for the same element. 3. Which check is acceptable inside a page object according to the Selenium documentation? Verifying, while the object is created, that the right page has loaded Asserting that the welcome message contains the user's name Asserting that an error message matches the expected text The docs say page objects should never make verifications, except checking that the page and critical elements loaded correctly, done at instantiation. Outcome checks belong in the test. 4. A login can succeed, or fail with an error on the same page. What is the cleanest page object API for that? One `login()` method returning `Object`, cast by the test `loginAs()` returning `LoggedInPage` and `loginExpectingError()` returning `LoginPage` One `login(boolean expectSuccess)` method that asserts the outcome Separate methods make each expected outcome explicit in the test and give it a precise return type. A boolean flag plus internal assertions hides the expectation in the page object. 5. `By.linkText("Practice")` finds nothing in the practice site's menu, while the DOM text is "Practice". Why? The link is inside an iframe `linkText` only works on buttons CSS `text-transform` renders it as "PRACTICE", and Selenium matches the rendered text Selenium's link text uses what is rendered. Matching on DOM text (an XPath `normalize-space()` predicate, or Playwright's accessible name) keeps the locator independent of styling. 6. What is the main practical problem with `@FindBy` fields and `PageFactory.initElements(driver, this)`? Waiting is hidden in the locator factory and limited to presence, so explicit visibility or clickability waits are still needed It was removed in Selenium 4 and no longer compiles Proxy fields always throw `StaleElementReferenceException` Page Factory still ships and is not deprecated, but its docs are in the Legacy section. Proxies re-find elements on each call; staleness only appears with `@CacheLookup`. 7. A TestNG class stores `WebDriver driver` in an instance field set in `@BeforeMethod`, and the suite runs with `parallel="methods"`. What happens? Each method gets its own class instance, so it works Threads overwrite each other's driver: tests drive the wrong browser, hit quit sessions, and leak browsers TestNG detects the shared field and runs the methods sequentially TestNG shares one instance across threads. A `ThreadLocal` driver, cleared with `remove()` after `quit()`, gives every thread its own browser. 8. With pytest-xdist (`pytest -n 4`), a fixture has `scope="session"`. How often does it run? Once for the whole run Once per test Once per worker process xdist workers are separate processes, each with its own session. That isolation is why Python needs no ThreadLocal, and why "run once" setup must be designed for several workers. 9. A Playwright test fails, then passes on retry. Which setting makes the run fail anyway, so the flakiness is not hidden? `failOnFlakyTests: true` (or `--fail-on-flaky-tests`) `trace: 'on-first-retry'` `retries: 0` in the test file Playwright marks such tests "flaky", and `failOnFlakyTests` turns that into a failed run. Trace settings only control evidence; they do not change the result. 10. Your page objects need to run on a remote grid instead of local browsers. With the framework from this course, what changes? Every page object gets a remote-aware constructor Only config: the driver factory, pytest fixture or Playwright project creates a remote session Tests must switch from `By` locators to XPath Page objects only depend on a `WebDriver` or `Page`. Where that browser runs is decided in one place in the framework layer, which is the point of separating the layers. Check answers Next, put the framework to work: our [Selenium with Java and TestNG course](https://testingbot.com/resources/courses/selenium-testng) goes deeper into the runner used in chapters 01-07, and the [Playwright Test documentation](https://testingbot.com/support/web-automate/playwright/playwright-test) shows the full configuration for running these specs on TestingBot. [Previous · Chapter 9 POM Anti-Patterns and When to Skip POM](https://testingbot.com/resources/courses/page-object-model/anti-patterns) ## You finished Page Object Model and Framework Design Put what you learned into practice. 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