01
How do you validate a JSON response in REST Assured?
Show answer
Use then().statusCode(200).body("data.id", equalTo(5)), or extract() the response and assert fields with JsonPath.
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02
How do you run tests in parallel?
Show answer
Use TestNG parallel="methods | classes | tests" with thread-count, keep WebDriver in a ThreadLocal, and use Selenium Grid or a cloud grid for multiple browsers.
03
How do you verify that an element is displayed, enabled or selected?
Show answer
Use isDisplayed(), isEnabled() and isSelected() on the WebElement before interacting or asserting.
04
Write an XPath for a button with the text "Login".
Show answer
//button[normalize-space()='Login']
//button[contains(text(),'Login')]
05
How do you take a screenshot on failure in TestNG?
Show answer
Implement ITestListener.onTestFailure():
File src = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
then copy it into the reports folder.
06
How do you verify response time and headers in REST Assured?
Show answer
Use then().time(lessThan(2000L)) and then().header("Content-Type", containsString("json")) along with body assertions.
07
How do you handle a dropdown that is not a <select> tag?
Show answer
Click to open the dropdown, then locate the option by its text, e.g. //li[text()='India'], and click it. Add an explicit wait for the animation.
08
How do you handle environment-specific configuration?
Show answer
Keep URLs and credentials in per-environment config files or variables, choose with a command-line parameter and never hard-code secrets.
09
How do you pass parameters from testng.xml?
Show answer
Define parameter name and value in the XML and read them with @Parameters in the test or configuration method.
10
How do you read data from Excel or properties files in Java?
Show answer
Use Apache POI for Excel and the Properties class for config files, loaded in a utility class so tests read data instead of hard-coding it.
11
What is the execution order of TestNG annotations?
Show answer
@BeforeSuite → @BeforeTest → @BeforeClass → @BeforeMethod → @Test → @AfterMethod → @AfterClass → @AfterTest → @AfterSuite.
12
How do you group tests?
Show answer
Tag tests with groups = {"smoke","regression"} and include or exclude them in testng.xml to run chosen sets.
13
How do you upload a file with Selenium?
Show answer
If the element is <input type="file">, use element.sendKeys("C:/path/file.pdf"). Use the Robot class or AutoIt only as a last resort for OS dialogs.
14
How do you retry failed tests in TestNG?
Show answer
Implement IRetryAnalyzer with a retry count and attach it through the test annotation or a listener to rerun flaky tests.
15
How do you run JavaScript in Selenium?
Show answer
Cast the driver to JavascriptExecutor and use executeScript, for example to scroll into view or click hidden elements.
16
How do you handle iframes?
Show answer
switchTo().frame(index, name or element) enters the frame, and switchTo().defaultContent() returns to the main page.
17
How do you scroll a page in Selenium?
Show answer
Use JavascriptExecutor with window.scrollTo or scrollIntoView, or the Actions class scroll methods in Selenium 4.
18
How do you handle a web table in Selenium?
Show answer
Locate rows and columns with XPath such as //table//tr and //td, loop through them to read or click cells, or build the XPath dynamically from the row text.
19
Write a GET test in REST Assured.
Show answer
given().baseUri(url)
.when().get("/users/1")
.then().statusCode(200).body("id", equalTo(1));
20
How do you integrate Selenium tests with Jenkins?
Show answer
Create a job or pipeline that checks out code, runs mvn test, publishes reports and triggers on commits or schedules.
21
How do you switch between windows and tabs?
Show answer
Get getWindowHandles(), loop to find the target, and call driver.switchTo().window(handle); switch back using the stored parent handle.
22
How do you manage test data in a framework?
Show answer
Use external files or APIs and database setup scripts, generate unique data per run, and clean up afterwards so tests stay independent.
23
How do you handle multiple windows?
Show answer
String parent = driver.getWindowHandle();
for (String h : driver.getWindowHandles())
if (!h.equals(parent)) driver.switchTo().window(h);
// ...then switch back to parent
24
How do you handle alerts and pop-ups?
Show answer
driver.switchTo().alert() lets you accept, dismiss, read text or send keys. Browser windows are handled with window handles.
25
What is a DataProvider in TestNG?
Show answer
@DataProvider returns Object[][]; a @Test(dataProvider = "name") method runs once per row — the basis of data-driven tests, often reading Excel or JSON.
26
How do you make WebDriver thread-safe for parallel runs?
Show answer
Store each driver in a ThreadLocal so every thread gets its own instance and tests do not interfere.
27
How do you pass authentication in an API test?
Show answer
Use headers such as Bearer tokens, basic auth, API keys or OAuth flows; fetch a token in a setup step and reuse it.
28
How do you handle dropdowns in Selenium?
Show answer
Use the Select class with selectByVisibleText, selectByValue or selectByIndex; for custom dropdowns click and choose from the list of elements.
29
Reverse a string in Java.
Show answer
String r = new StringBuilder(s).reverse().toString();
// or loop from the last index and append each character
30
How do you run only selected scenarios using tags in Cucumber?
Show answer
Add tags like @smoke or @regression above a Feature or Scenario, then filter with a tag expression. In the runner use @ConfigurationParameter(key = FILTER_TAGS_PROPERTY_NAME, value = "@smoke and not @wip") with the JUnit Platform engine, or pass -Dcucumber.filter.tags="@smoke" from Maven. Tag expressions support and, or, not and brackets, so CI can run smoke on every commit and regression nightly.
31
Write a step definition that reads a DataTable as a list of maps.
Show answer
// Given the following users exist
@Given("the following users exist")
public void usersExist(DataTable table) {
List<Map<String, String>> rows = table.asMaps();
for (Map<String, String> row : rows) {
userApi.create(row.get("name"), row.get("role"));
}
}
32
How do you attach a screenshot to the Cucumber report when a scenario fails?
Show answer
@After
public void afterScenario(Scenario scenario) {
if (scenario.isFailed()) {
byte[] shot = ((TakesScreenshot) driver)
.getScreenshotAs(OutputType.BYTES);
scenario.attach(shot, "image/png", scenario.getName());
}
driver.quit();
}
33
How do you generate reports from Cucumber?
Show answer
Configure plugins such as pretty for console, html:target/cucumber.html for a built-in report and json:target/cucumber.json for tools. The JSON feeds maven-cucumber-reporting or the Jenkins Cucumber Reports plugin. For richer dashboards, add the Allure or Extent Cucumber adapter. Attach screenshots and logs in hooks so failures can be analysed from the report alone.
34
How do you rerun only failed Cucumber scenarios?
Show answer
Add the rerun plugin, for example rerun:target/failed.txt, to the main runner. It writes the location of each failed scenario. Create a second runner whose features point to @target/failed.txt and run it after the main run in Maven or Jenkins. Use reruns to separate real failures from flaky ones, but track flaky scenarios and fix them instead of hiding them.
35
Write a Scenario Outline for login with three data sets.
Show answer
Scenario Outline: Login with different users
Given the user is on the login page
When the user logs in with "<username>" and "<password>"
Then the message "<message>" is shown
Examples:
| username | password | message |
| asha | Valid@1 | Welcome Asha |
| asha | wrong | Invalid password |
| locked1 | Valid@1 | Account is locked |
36
How do you create a custom parameter type in Cucumber?
Show answer
Annotate a method with @ParameterType, giving a regex and returning a domain object. For example @ParameterType("admin|manager|viewer") public Role role(String name) { return Role.valueOf(name.toUpperCase()); } lets you write steps like "I log in as {role}". It keeps conversion logic in one place, makes steps type-safe and gives clearer errors when an invalid value is used.
37
How do you use Cucumber with REST Assured for API BDD tests?
Show answer
Write scenarios in business terms, such as "When a customer places an order for 2 items". In step definitions, build the request with REST Assured, store the Response in a shared scenario context, and assert in Then steps using then().statusCode() and JSON path checks. Keep base URI, auth and specs in a helper class so steps stay short and the same steps serve many features.
38
Write a REST Assured POST test that sends a JSON body and checks the response.
Show answer
@Test
public void createUser() {
String body = "{\"name\":\"Ravi\",\"job\":\"QA\"}";
given()
.baseUri("https://api.example.com")
.contentType(ContentType.JSON)
.body(body)
.when()
.post("/users")
.then()
.statusCode(201)
.body("name", equalTo("Ravi"))
.body("id", notNullValue());
}
39
How do you extract a value from one response and use it in the next request?
Show answer
String token = given().body(creds).when().post("/login")
.then().statusCode(200)
.extract().path("token");
given()
.header("Authorization", "Bearer " + token)
.when()
.get("/orders")
.then()
.statusCode(200);
40
How do you validate a response against a JSON schema in REST Assured?
Show answer
Add the json-schema-validator dependency, place the schema file in src/test/resources, and assert with then().body(matchesJsonSchemaInClasspath("user-schema.json")). Schema validation checks field types, required fields and structure, so it catches contract changes that value checks might miss. It complements, not replaces, assertions on business values like status or totals.
41
Write a REST Assured test that deserializes a response into a POJO.
Show answer
@Test
public void getUserAsPojo() {
User user = given()
.pathParam("id", 2)
.when()
.get("/users/{id}")
.then()
.statusCode(200)
.extract().as(User.class);
Assert.assertEquals(user.getId(), 2);
Assert.assertNotNull(user.getEmail());
}
42
How do you upload a file with REST Assured?
Show answer
Use multipart: given().multiPart("file", new File("src/test/resources/report.pdf"), "application/pdf").formParam("type", "invoice").when().post("/upload").then().statusCode(200). REST Assured sets the multipart/form-data content type automatically. Verify both the status and the response, such as the returned file id or size, and test edge cases like empty, oversized and wrong-type files.
43
How do you assert on an array in a JSON response using Hamcrest?
Show answer
Use collection matchers inside body(). For example body("data.id", hasItems(1, 2)), body("data", hasSize(6)), body("data.email", everyItem(containsString("@"))) and body("data.find { it.id == 3 }.name", equalTo("Neha")). These check the whole collection in one line. For complex rules, extract a List with jsonPath().getList() and assert with Java or AssertJ.
44
How do you send form parameters and headers in REST Assured?
Show answer
Use formParam("username", "asha") and formParam("password", "pass") for application/x-www-form-urlencoded bodies; REST Assured sets the content type for you. Add headers with header("X-Client", "web") or headers(map) for many at once. Cookies use cookie(name, value). Keep common headers in a RequestSpecification so individual tests only add what is specific to them.
45
Write a REST Assured test using RequestSpecBuilder and ResponseSpecBuilder.
Show answer
RequestSpecification req = new RequestSpecBuilder()
.setBaseUri(Config.baseUrl())
.setContentType(ContentType.JSON)
.addHeader("Authorization", "Bearer " + token)
.build();
ResponseSpecification ok = new ResponseSpecBuilder()
.expectStatusCode(200)
.expectContentType(ContentType.JSON)
.build();
given().spec(req).when().get("/orders").then().spec(ok);
46
Write a simple page object class for a login page.
Show answer
public class LoginPage {
private final WebDriver driver;
private final By user = By.id("username");
private final By pass = By.id("password");
private final By submit = By.cssSelector("button[type='submit']");
public LoginPage(WebDriver driver) { this.driver = driver; }
public HomePage loginAs(String u, String p) {
driver.findElement(user).sendKeys(u);
driver.findElement(pass).sendKeys(p);
driver.findElement(submit).click();
return new HomePage(driver);
}
}
47
How do you verify that the correct page has loaded in POM?
Show answer
Give each page an isAt() or waitUntilLoaded() method that waits for a unique element, page title or URL fragment. Call it in the constructor or right after navigation. If it fails, throw a clear error such as "Expected Cart page but URL was /login". This catches navigation problems at the right point instead of failing later with a confusing locator error.
48
Write a BasePage helper that clicks an element after waiting for it to be clickable.
Show answer
public abstract class BasePage {
protected final WebDriver driver;
protected final WebDriverWait wait;
protected BasePage(WebDriver driver) {
this.driver = driver;
this.wait = new WebDriverWait(driver, Duration.ofSeconds(10));
}
protected void click(By locator) {
wait.until(ExpectedConditions.elementToBeClickable(locator)).click();
}
}
49
How do you make page objects work with dynamic locators, such as a row containing a given name?
Show answer
Write a method that builds the locator from a parameter, for example private By rowFor(String name) { return By.xpath("//tr[td[normalize-space()='" + name + "']]"); }, and expose actions like deleteUser(name). Keep the template in the page class, not in tests. Escape quotes if names may contain them, and prefer CSS with data attributes when the application provides them.
50
How do you resolve a merge conflict in Git?
Show answer
Git marks conflicting sections with <<<<<<<, ======= and >>>>>>>. Open each file, decide which change to keep or combine both, remove the markers, then git add the files and complete with git commit (or git rebase --continue). Run the affected tests before pushing. Pull often and keep branches short-lived to reduce conflicts.
51
How do you pass parameters like browser and environment from Maven to your tests?
Show answer
Pass system properties on the command line, for example mvn test -Dbrowser=firefox -Denv=qa. Read them in Java with System.getProperty("browser", "chrome"), giving a default. Surefire forwards -D properties to the forked test JVM, or you can declare them under systemPropertyVariables. Jenkins can expose these as build parameters so testers choose browser and environment per run.
52
Write a declarative Jenkinsfile that runs Maven tests and publishes results.
Show answer
pipeline {
agent any
parameters { choice(name: 'SUITE', choices: ['smoke', 'regression']) }
stages {
stage('Checkout') { steps { checkout scm } }
stage('Test') {
steps { sh "mvn clean test -DsuiteXml=${params.SUITE}.xml" }
}
}
post {
always {
junit 'target/surefire-reports/*.xml'
archiveArtifacts artifacts: 'target/screenshots/**', allowEmptyArchive: true
}
}
}
53
How do you run tests on multiple browsers in parallel in Jenkins?
Show answer
Use a parallel block in the pipeline with a stage per browser, or a matrix directive with axis BROWSER values chrome, firefox and edge. Each branch runs mvn test -Dbrowser=${BROWSER}, ideally against Selenium Grid or containers so agents do not need local browsers. Publish results per branch with clear names so failures show which browser broke.
54
How do you publish Allure or Extent reports from Jenkins?
Show answer
For Allure, install the Allure Jenkins plugin, configure the commandline tool, and add allure results: [[path: 'target/allure-results']] in the post always block. For Extent, archive the HTML file and use the HTML Publisher plugin to show it as a build link. Keep report history per build and share the link in failure notifications.
55
How do you mock an external API in automation tests?
Show answer
Use a tool such as WireMock or MockServer to run a stub server that returns predefined responses for given requests. Point the application or tests to the stub with configuration. This lets you test error codes, timeouts and edge cases that are hard to trigger on the real service, and keeps tests stable when the third party is down. Still keep a few tests against the real integration.
56
How do you run Selenium tests in Docker containers in CI?
Show answer
Use official Selenium images, either standalone-chrome for simple runs or a Grid with hub and node containers via Docker Compose. The test container or Jenkins agent points RemoteWebDriver to http://selenium-hub:4444. Containers give the same browser version everywhere and are cleaned after each run. Add shm_size for Chrome stability and record videos for failed tests if needed.
57
How do you test that a method throws an expected exception in TestNG?
Show answer
Use @Test(expectedExceptions = IllegalArgumentException.class) and optionally expectedExceptionsMessageRegExp to check the message. The test passes only if that exception is thrown. For more control, use Assert.assertThrows(IllegalArgumentException.class, () -> service.withdraw(-5)), which returns the exception so you can inspect it further. This style is clearer because the check applies to one line, not the whole test.
58
Write a TestNG listener that logs test start and failure.
Show answer
public class LogListener implements ITestListener {
@Override
public void onTestStart(ITestResult r) {
System.out.println("START: " + r.getMethod().getMethodName());
}
@Override
public void onTestFailure(ITestResult r) {
System.out.println("FAIL: " + r.getName() + " - " + r.getThrowable());
}
}
// register with @Listeners(LogListener.class) or <listeners> in testng.xml
59
How do you include and exclude groups in testng.xml?
Show answer
Inside a <test>, add <groups><run><include name="smoke"/><exclude name="broken"/></run></groups>. Only methods in the included groups run, minus excluded ones. Configuration methods must have alwaysRun = true or belong to the groups, or they will be skipped. You can also pass -Dgroups=smoke from Maven Surefire for CI selection.
60
How do you run the same test with data from Excel using a DataProvider?
Show answer
Write a utility that reads the sheet with Apache POI and returns Object[][] with one row per test case. Create a @DataProvider method that calls the utility, and set dataProvider = "loginData" on the test. Each row runs as a separate test with its own result. Keep the file in src/test/resources and consider CSV or JSON, which are easier to review in Git.
61
Write a REST Assured test for a DELETE request followed by a check that the resource is gone.
Show answer
@Test
public void deleteUser() {
int id = createTestUser();
given().spec(req).pathParam("id", id)
.when().delete("/users/{id}")
.then().statusCode(204);
given().spec(req).pathParam("id", id)
.when().get("/users/{id}")
.then().statusCode(404);
}
62
Write a REST Assured PUT test that updates a resource using a POJO.
Show answer
@Test
public void updateUser() {
User update = new User("Ravi", "Lead QA");
given().spec(req)
.pathParam("id", 7)
.body(update)
.when()
.put("/users/{id}")
.then()
.statusCode(200)
.body("job", equalTo("Lead QA"));
}
63
Write a DataProvider that supplies two sets of login data and a test that uses it.
Show answer
@DataProvider(name = "logins")
public Object[][] logins() {
return new Object[][] {
{"asha", "Valid@1", true},
{"asha", "wrong", false}
};
}
@Test(dataProvider = "logins")
public void login(String user, String pass, boolean ok) {
boolean result = loginPage.loginAs(user, pass).isLoggedIn();
Assert.assertEquals(result, ok);
}
64
Write Java code to find duplicate elements in a list.
Show answer
List<String> names = List.of("Asha", "Ravi", "Asha", "Neha", "Ravi");
Set<String> seen = new HashSet<>();
Set<String> dupes = new LinkedHashSet<>();
for (String n : names) {
if (!seen.add(n)) {
dupes.add(n);
}
}
System.out.println(dupes); // [Asha, Ravi]
65
Write Java code to count the occurrences of each character in a string.
Show answer
String s = "automation";
Map<Character, Integer> counts = new LinkedHashMap<>();
for (char c : s.toCharArray()) {
counts.put(c, counts.getOrDefault(c, 0) + 1);
}
System.out.println(counts);
// a=2, u=1, t=2, o=2, m=1, i=1, n=1
66
Write a Java stream that extracts and sorts product prices from a list of WebElements.
Show answer
List<Double> prices = driver.findElements(By.cssSelector(".price"))
.stream()
.map(WebElement::getText)
.map(t -> t.replaceAll("[^0-9.]", ""))
.map(Double::parseDouble)
.sorted()
.collect(Collectors.toList());
System.out.println(prices);
67
How do you handle an element inside a shadow DOM in Selenium 4?
Show answer
Find the shadow host element, then call getShadowRoot() to get a SearchContext, and search inside it with CSS selectors: driver.findElement(By.cssSelector("my-app")).getShadowRoot().findElement(By.cssSelector("#submit")). XPath does not work inside shadow roots. For nested shadow roots, repeat the step for each host. Closed shadow roots cannot be accessed this way.
68
Write Selenium code to wait for a loader to disappear and then click a button.
Show answer
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(15));
wait.until(ExpectedConditions.invisibilityOfElementLocated(
By.cssSelector(".spinner")));
wait.until(ExpectedConditions.elementToBeClickable(
By.id("placeOrder"))).click();
69
Write Selenium code to verify that all links on a page are not broken.
Show answer
List<WebElement> links = driver.findElements(By.tagName("a"));
for (WebElement link : links) {
String url = link.getAttribute("href");
if (url == null || !url.startsWith("http")) continue;
HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
con.setRequestMethod("HEAD");
int code = con.getResponseCode();
if (code >= 400) System.out.println("Broken: " + url + " " + code);
}
70
How do you switch between native and webview contexts in a hybrid app?
Show answer
// Requires the webview to be debuggable in the app build
Set<String> contexts = driver.getContextHandles();
for (String ctx : contexts) {
if (ctx.startsWith("WEBVIEW")) {
driver.context(ctx);
break;
}
}
driver.findElement(By.cssSelector("#email")).sendKeys("qa@test.com");
// back to native controls
driver.context("NATIVE_APP");
71
Write Appium Java code to perform a vertical swipe using W3C Actions.
Show answer
// Swipe up from 80% to 20% of the screen height
Dimension size = driver.manage().window().getSize();
int x = size.width / 2;
int startY = (int) (size.height * 0.8);
int endY = (int) (size.height * 0.2);
PointerInput finger = new PointerInput(PointerInput.Kind.TOUCH, "finger");
Sequence swipe = new Sequence(finger, 1);
swipe.addAction(finger.createPointerMove(Duration.ZERO, PointerInput.Origin.viewport(), x, startY));
swipe.addAction(finger.createPointerDown(PointerInput.MouseButton.LEFT.asArg()));
swipe.addAction(finger.createPointerMove(Duration.ofMillis(600), PointerInput.Origin.viewport(), x, endY));
swipe.addAction(finger.createPointerUp(PointerInput.MouseButton.LEFT.asArg()));
driver.perform(List.of(swipe));
72
Write Java code to start an Android Appium session using UiAutomator2Options.
Show answer
UiAutomator2Options options = new UiAutomator2Options()
.setPlatformName("Android")
.setAutomationName("UiAutomator2")
.setDeviceName("Pixel_7_API_34")
.setApp(System.getProperty("user.dir") + "/apps/shop.apk")
.setAutoGrantPermissions(true)
.setNewCommandTimeout(Duration.ofSeconds(120));
AndroidDriver driver = new AndroidDriver(
new URL("http://127.0.0.1:4723"), options);
driver.manage().timeouts().implicitlyWait(Duration.ZERO);
// use explicit waits in tests
driver.quit();
73
Write Appium code to scroll to an element by its text using UiScrollable on Android.
Show answer
// Scrolls the first scrollable container until the text is visible
String selector = "new UiScrollable(new UiSelector().scrollable(true))"
+ ".scrollIntoView(new UiSelector().text(\"Order History\"))";
WebElement item = driver.findElement(AppiumBy.androidUIAutomator(selector));
item.click();
74
How do you run Appium tests in parallel on several Android devices?
Show answer
Give each device its own session: unique appium:udid, a separate appium:systemPort for UiAutomator2 and, for hybrid apps, a separate chromedriverPort. Store the driver in a ThreadLocal so threads never share it. Pass device details through TestNG parameters or a DataProvider and run with parallel="tests", one test tag per device. One Appium server can handle several sessions, or use a Selenium Grid 4 with Appium nodes or a cloud device farm for larger matrices.
75
How do you test deep links in a mobile app with Appium?
Show answer
On Android use the mobile: deepLink command with the URL and package, for example driver.executeScript("mobile: deepLink", Map.of("url", "shop://product/42", "package", "com.example.shop")). On iOS simulators driver.get with the custom URL opens it, though Safari may show a confirm dialog to handle. Then assert that the correct screen and data are shown. Deep links are also a great shortcut to reach deep screens quickly in other tests.
76
How do you capture a screen recording of a mobile test and attach it on failure?
Show answer
// Start before the test, stop and save only if it fails
driver.startRecordingScreen();
// ... test steps ...
String base64 = driver.stopRecordingScreen();
if (result.getStatus() == ITestResult.FAILURE) {
byte[] video = Base64.getDecoder().decode(base64);
Files.write(Paths.get("target/videos/" + result.getName() + ".mp4"), video);
}
77
Write Java code to find the second largest number in an integer array.
Show answer
public static int secondLargest(int[] nums) {
int first = Integer.MIN_VALUE, second = Integer.MIN_VALUE;
for (int n : nums) {
if (n > first) {
second = first;
first = n;
} else if (n > second && n != first) {
second = n;
}
}
if (second == Integer.MIN_VALUE) throw new IllegalArgumentException("No second largest");
return second;
}
78
How do you handle a browser basic authentication pop-up in Selenium?
Show answer
The basic auth dialog is not part of the page, so findElement cannot reach it. The simplest way is putting credentials in the URL, like https://user:pass@site.test, which works in many browsers. In Selenium 4 with Chromium you can register credentials through the HasAuthentication interface: ((HasAuthentication) driver).register(UsernameAndPassword.of("user", "pass")). Keep the credentials in environment variables or a secret store, never in code.
79
How do you watch a test running inside a Docker Selenium container?
Show answer
The selenium node and standalone images include a VNC server and noVNC. Expose port 7900 and open http://localhost:7900 in a browser; the default password is secret, or set SE_VNC_NO_PASSWORD to skip it. You can also open the Grid UI on port 4444 and click the session's video icon. This is very useful for debugging tests that fail only inside the container, such as layout or focus problems.
80
Write a docker-compose.yml that runs a Selenium hub with Chrome and Firefox nodes.
Show answer
services:
selenium-hub:
image: selenium/hub:4.25.0
ports:
- "4442:4442"
- "4443:4443"
- "4444:4444"
chrome:
image: selenium/node-chrome:4.25.0
shm_size: 2gb
depends_on:
- selenium-hub
environment:
- SE_EVENT_BUS_HOST=selenium-hub
- SE_EVENT_BUS_PUBLISH_PORT=4442
- SE_EVENT_BUS_SUBSCRIBE_PORT=4443
firefox:
image: selenium/node-firefox:4.25.0
shm_size: 2gb
depends_on:
- selenium-hub
environment:
- SE_EVENT_BUS_HOST=selenium-hub
- SE_EVENT_BUS_PUBLISH_PORT=4442
- SE_EVENT_BUS_SUBSCRIBE_PORT=4443
81
Write Java code to create a RemoteWebDriver for a Selenium Grid using ChromeOptions.
Show answer
String gridUrl = System.getProperty("grid.url", "http://localhost:4444");
ChromeOptions options = new ChromeOptions();
options.addArguments("--window-size=1920,1080");
options.setCapability("se:name", "Login smoke test");
WebDriver driver = new RemoteWebDriver(new URL(gridUrl), options);
try {
driver.get("https://app.test/login");
} finally {
driver.quit();
}
82
Write a Dockerfile that runs a Maven and TestNG test suite.
Show answer
FROM maven:3.9-eclipse-temurin-21
WORKDIR /app
# cache dependencies first for faster rebuilds
COPY pom.xml .
RUN mvn -q dependency:go-offline
COPY src ./src
COPY testng.xml .
ENV GRID_URL=http://selenium-hub:4444
CMD ["sh", "-c", "mvn test -Dgrid.url=$GRID_URL -Dsurefire.suiteXmlFiles=testng.xml"]
83
How do you check that the Grid is ready before starting the tests in CI?
Show answer
Poll the Grid status endpoint, http://hub:4444/status, until the JSON field value.ready is true, which means at least one node has registered. In a shell step you can loop with curl and jq, for example until curl -s http://localhost:4444/status | jq -e '.value.ready'; do sleep 2; done, with an overall timeout. In Compose you can add a healthcheck on the hub. Without this, the first tests fail while nodes are still starting.
84
How do you increase the number of Chrome nodes with Docker Compose?
Show answer
Use the scale option: docker compose up -d --scale chrome=4 starts four Chrome node containers from the same service definition, and each registers with the hub. Do not fix container names or host ports on a scaled service, or the extra containers will clash. Check the Grid UI on port 4444 to confirm the slots. Make sure the host has enough CPU and memory, roughly one CPU core and 1 to 2 GB per browser.
85
How do you start a standalone Chrome container and run your tests against it?
Show answer
Run docker run -d -p 4444:4444 -p 7900:7900 --shm-size=2g selenium/standalone-chrome:latest, preferably with a pinned version tag instead of latest. It starts a mini Grid with one Chrome node. Point RemoteWebDriver to http://localhost:4444 with ChromeOptions and the tests run inside the container. Port 7900 lets you watch through noVNC. Stop it with docker stop when finished, or use --rm so it is removed automatically.
86
How do you record videos of tests running on a Docker Selenium Grid?
Show answer
Add the selenium/video image as a sidecar container next to each node, sharing the node's display through DISPLAY_CONTAINER_NAME, and mount a folder for the mp4 files. Newer Grid versions also support recording per session by setting the se:recordVideo capability with Dynamic Grid. Name videos with se:name so they match test names. Keep videos only for failed tests or for a few days, because they use a lot of disk space.
87
How do you set up distributed load testing in JMeter?
Show answer
One controller machine coordinates several worker machines that generate the load. On each worker start jmeter-server with the same JMeter and Java versions, place CSV files locally and open the RMI ports in the firewall. On the controller list the workers in remote_hosts in jmeter.properties, or pass -R host1,host2, and run in non-GUI mode with -r or -R. Remember that thread counts multiply per worker, so 100 threads on 4 workers gives 400 users.
88
Write the command to run a JMeter test in non-GUI mode and generate the HTML report.
Show answer
# -n non-GUI, -t test plan, -l results file, -e -o HTML dashboard folder
jmeter -n -t tests/checkout.jmx \
-l results/checkout.jtl \
-e -o results/html-report \
-Jusers=100 -Jrampup=60 -Jduration=600
# generate a report later from an existing JTL
jmeter -g results/checkout.jtl -o results/html-report-2
89
How do you extract an auth token with JSON Extractor and use it in later JMeter requests?
Show answer
Add a JSON Extractor as a child of the login sampler. Set the variable name to token, the JSON path expression to $.access_token, match number 1 and a default like TOKEN_NOT_FOUND so failures are visible. Then add an HTTP Header Manager at Thread Group level with Authorization set to Bearer ${token}. Each thread extracts and uses its own token, because JMeter variables are per thread.
90
Write a JSR223 Groovy PostProcessor that reads a JSON response and stores a value as a JMeter variable.
Show answer
// JSR223 PostProcessor, language: groovy
import groovy.json.JsonSlurper
def body = prev.getResponseDataAsString()
def json = new JsonSlurper().parseText(body)
if (json?.orderId) {
vars.put('orderId', json.orderId.toString())
} else {
prev.setSuccessful(false)
prev.setResponseMessage('orderId missing in response')
}
91
How do you record a JMeter script with the HTTP(S) Test Script Recorder?
Show answer
Add the recorder from Templates using the Recording template, which also creates a Thread Group and Recording Controller. Start the recorder on port 8888, set your browser or system proxy to localhost:8888 and import the ApacheJMeterTemporaryRootCA certificate so HTTPS works. Perform the user journey, then stop. Afterwards remove static resources and third-party calls, add correlation for dynamic values, parameterize data and add think time.
92
How do you run JMeter tests in a Jenkins pipeline and fail the build when an SLA is breached?
Show answer
Run JMeter in non-GUI mode in a pipeline stage, ideally inside a Docker image with a pinned JMeter version, and archive the JTL and HTML report. Enforce SLAs with Duration Assertions or a JSR223 check, or parse the JTL in a script that compares 95th percentile and error rate with thresholds and exits non-zero. The Jenkins Performance plugin can also mark builds unstable or failed based on thresholds and trends.
93
How do you pass thread count and duration to a JMeter test from the command line?
Show answer
// In the Thread Group fields use property functions with defaults
Number of Threads: ${__P(users,10)}
Ramp-up period: ${__P(rampup,30)}
Duration (seconds): ${__P(duration,300)}
// Then override them when running
jmeter -n -t load.jmx -l out.jtl -Jusers=200 -Jrampup=120 -Jduration=1800
94
How do you validate an XML response in REST Assured?
Show answer
// REST Assured uses GPath for XML as well as JSON
given()
.accept(ContentType.XML)
.when()
.get("/orders/42")
.then()
.statusCode(200)
.contentType(ContentType.XML)
.body("order.@id", equalTo("42"))
.body("order.items.item.size()", equalTo(3))
.body("order.status", equalTo("SHIPPED"));
95
How do you test a responsive page in a mobile viewport using Selenium?
Show answer
For layout checks you can set the window size, like driver.manage().window().setSize(new Dimension(390, 844)). For closer emulation in Chrome use mobile emulation in ChromeOptions: options.setExperimentalOption("mobileEmulation", Map.of("deviceName", "Pixel 7")), which also sets the user agent, pixel ratio and touch events. This catches responsive layout bugs quickly, but it is not a replacement for testing on real mobile browsers.
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