--- title: Knowledge check | Selenium Java Tutorial with TestNG description: Ten questions on the decisions this course made and why; each answer explains the reasoning once you check. 1. A teammate's README says to download… source_url: html: https://testingbot.com/resources/courses/selenium-testng/knowledge-check md: https://testingbot.com/resources/courses/selenium-testng/knowledge-check.md --- Course [Selenium Java Tutorial with TestNG](https://testingbot.com/resources/courses/selenium-testng) Chapter 11 of 11 1. [1 Selenium and TestNG: how they fit together](https://testingbot.com/resources/courses/selenium-testng) 2. [2 Set up a Maven project for Selenium](https://testingbot.com/resources/courses/selenium-testng/project-setup) 3. [3 Your first Selenium test with TestNG](https://testingbot.com/resources/courses/selenium-testng/first-test) 4. [4 TestNG annotations and the driver lifecycle](https://testingbot.com/resources/courses/selenium-testng/annotations) 5. [5 Hard assertions vs SoftAssert](https://testingbot.com/resources/courses/selenium-testng/assertions) 6. [6 Data-driven tests with DataProvider](https://testingbot.com/resources/courses/selenium-testng/data-providers) 7. [7 Suites, groups and parameters in testng.xml](https://testingbot.com/resources/courses/selenium-testng/testng-xml) 8. [8 Run Selenium tests in parallel](https://testingbot.com/resources/courses/selenium-testng/parallel-execution) 9. [9 Listeners, screenshots and reports](https://testingbot.com/resources/courses/selenium-testng/listeners-and-reports) 10. [10 Run the suite on a Selenium grid](https://testingbot.com/resources/courses/selenium-testng/run-on-a-selenium-grid) 11. [11 Knowledge check](https://testingbot.com/resources/courses/selenium-testng/knowledge-check) [Exit course](https://testingbot.com/resources/courses) Chapter 11 of 11 Intermediate 6 min read Updated Nov 2026 # Knowledge check Ten questions on the decisions this course made and why; each answer explains the reasoning once you check. 1. A teammate's README says to download chromedriver and set `webdriver.chrome.driver` before running the suite on Selenium 4.52. What is the best advice? Keep it: Selenium cannot start Chrome without a manually installed driver. Remove it: Selenium Manager resolves and caches a matching driver, and a stale driver on the PATH can cause version-mismatch errors. Replace it with a newer chromedriver checked into the repository. Since Selenium 4.6, Selenium Manager finds or downloads the right driver automatically. A manually placed driver takes precedence and is the usual cause of "this version of ChromeDriver only supports Chrome version N". 2. You upgrade maven-surefire-plugin from 3.5.6 to 3.6.1 and `mvn test` now stops before running anything. Why? Surefire 3.6 requires Java 25. TestNG 7.12 is not compatible with Maven 3.9. Surefire 3.6 runs TestNG on the JUnit Platform, which cannot read the `suiteXmlFiles` configured in the pom. From 3.6.0 all frameworks run through the JUnit Platform and `suiteXmlFiles` is rejected. Either stay on 3.5.x or replace suite files with groups and includes. 3. Every test method in a `` block is unexpectedly sharing one browser. Where was the driver most likely created? In a `@BeforeTest` method. In a `@BeforeMethod` method. In the test method itself. `@BeforeTest` runs once per `` tag in testng.xml, not per test method. Per-test browsers belong in `@BeforeMethod`. 4. You run `mvn test -Dgroups=smoke` and every smoke test fails with a NullPointerException on the driver. What is the fix? Add the smoke group to every test class. Add `alwaysRun = true` to the `@BeforeMethod` and `@AfterMethod` that manage the driver. Increase the explicit wait timeout. With a group filter, configuration methods that are not in that group are skipped unless they declare `alwaysRun = true`, so the driver is never created. 5. A test calls `Assert.assertEquals("Received!", message.getText())` and fails with "expected [Error] but found [Received!]". What happened? The page really showed "Received!" and the test is wrong to fail. TestNG swapped the values because of a bug. The arguments are in JUnit order; TestNG expects actual first, so the page showed "Error" and the message reads backwards. TestNG's signature is `assertEquals(actual, expected)`. Passing them JUnit-style still fails at the right time but produces a misleading message. 6. A test creates a `SoftAssert`, makes five checks, three of which fail, and the test passes. What is missing? A call to `softly.assertAll()` at the end of the test. A `@Listeners` annotation for SoftAssert. `alwaysRun = true` on the test. SoftAssert only records failures. `assertAll()` is what throws them; without it they are discarded and the test passes. 7. You set `parallel = true` on a data provider while the base class still keeps the driver in a plain instance field. What do you expect? It works, because each data row gets its own instance of the test class. Random failures such as NoSuchSessionException, because all rows share one instance and overwrite each other's driver. TestNG refuses to start because the provider is not static. All invocations of a data-driven test use the same instance. Without a `ThreadLocal`, threads replace and quit each other's browsers. 8. Your suite has `thread-count="3"` and a parallel data provider with 20 rows, yet far more than 3 browsers open at once. Why? `thread-count` is ignored when `parallel="methods"`. Selenium Manager starts extra browsers to warm its cache. Parallel data providers use a separate pool sized by `data-provider-thread-count`, which defaults to 10. The suite pool (3) and the data provider pool (default 10) are independent. Set `data-provider-thread-count` explicitly when browsers are a limited resource. 9. Your screenshot listener runs in `onTestFailure`, and the driver is quit in `@AfterMethod`. Does the screenshot show the failing page? Yes: TestNG calls `onTestFailure` before the `@AfterMethod` configuration methods, so the browser is still open. No: `@AfterMethod` always runs first, so the driver is already gone. Only if the listener is registered with `@Listeners` rather than testng.xml. With TestNG 7.12, `onTestFailure` runs on the test's thread before teardown, so `BaseTest.driver()` still returns the live session. Where the listener is registered does not change the order. 10. On a remote grid, a test fails on an assertion but the grid's dashboard shows the session as completed without a failure. Why, and what fixes it? The grid lost the result; rerun the test. The grid only sees WebDriver commands, not your assertions; report the outcome, for example with `tb:test-result=failed` via the JavaScript executor before `quit()`. Assertions are disabled on RemoteWebDriver; switch to SoftAssert. Assertions run in your JVM. The grid can only know the outcome if you send it, which the final `BaseTest` does in `@AfterMethod` using `ITestResult.isSuccess()`. Check answers ## Where to go next[#](https://testingbot.com#where-to-go-next) Your suite now has one browser per test, safe parallelism, screenshots on failure and a switch to run on a grid. The next step is structure: once several tests touch the same pages, move locators and page interactions into page objects, which the [Page Object Model course](https://testingbot.com/resources/courses/page-object-model) builds on top of a project like this one. If you are preparing for a job interview, the [test automation interview questions course](https://testingbot.com/resources/courses/selenium-interview-questions) has a chapter on TestNG questions. For the reference version of the grid setup, keep the [TestNG documentation](https://testingbot.com/support/web-automate/selenium/java/testng) at hand. [Previous · Chapter 10 Run the suite on a Selenium grid](https://testingbot.com/resources/courses/selenium-testng/run-on-a-selenium-grid) ## You finished Selenium Java Tutorial with TestNG Put what you learned into practice. Run your tests on 6100+ real browsers and physical iOS and Android devices. [Start free trial](https://testingbot.com/users/sign_up) [See pricing](https://testingbot.com/pricing) [Browse other courses](https://testingbot.com/resources/courses) ## Earn the TestingBot certification for this course Pass the exam and run the course suite on TestingBot. Free, with a public link you can add to LinkedIn. 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