200+ Sdet Automation Test Engineer Interview Questions and Answers

An interface in Java is a reference type, similar to a class, that can contain only constants, method signatures, default methods, static methods, and nested types.

• Interfaces in Java are used to achieve abstraction and multiple inheritance.

• Interfaces cannot have method bodies, only method signatures.

• Classes can implement multiple interfaces, but can only extend one class.

• Example: interface Shape { void draw(); }

• Example: class Circle implements Shape { public void draw() { Sys...read more

Using System.exit(0) in a try-catch block terminates the JVM, preventing further code execution.

• System.exit(0) is used to terminate the Java Virtual Machine (JVM) normally.

• Any code after System.exit(0) in the try block will not execute.

• Example: try { System.exit(0); System.out.println('This will not print'); } catch (Exception e) { e.printStackTrace(); }

• In a catch block, if System.exit(0) is called, it will also terminate the program immediately.

Using Try Catch block in a framework for handling exceptions

• Use Try block to enclose the code that might throw an exception

• Use Catch block to handle the exception if it occurs

• Use Finally block to execute code regardless of whether an exception was thrown or not

Java program to reverse a string using StringBuilder

• Create a StringBuilder object with the input string

• Use the reverse() method of StringBuilder to reverse the string

• Convert the StringBuilder object back to a string using toString() method

I have applied OOPS concepts in my automation framework by creating reusable classes for different functionalities.

• Used inheritance to create a base class with common methods for all test cases

• Implemented polymorphism by overriding methods in child classes for specific test cases

• Utilized encapsulation to hide the internal details of classes and expose only necessary methods and properties

Write a test script for a given scenario in any suitable framework

• Identify the scenario to be tested

• Create test data if needed

• Write test steps using the chosen framework

• Execute the test script and analyze results

OOP is a programming paradigm based on the concept of objects, which can contain data and methods.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Mechanism to create a new class using properties and methods of an existing class (e.g., a 'Dog' class inheriting from an 'Animal' class).

• Polymorphism: Ability to present the same interface for different underlying data types (e.g., a function that can take different typ...read more

Validate if purchase amount equals the product of copies and prices in a JSON structure.

• Check if the JSON has keys: 'purchaseAmount', 'copies', and 'price'.

• Example JSON: { 'purchaseAmount': 100, 'copies': 5, 'price': 20 }.

• Calculate expected amount: copies * price = 5 * 20 = 100.

• Compare calculated amount with purchaseAmount to validate.

• Return true if they match, else return false.

Stale element exception occurs when an element is no longer attached to the DOM. It can be overcome by re-locating the element.

• Stale element exception is a common issue in automation testing, especially in Selenium WebDriver.

• It occurs when an element that was located on a web page becomes stale, meaning it is no longer attached to the DOM.

• This can happen when the page is refreshed, updated, or changed in some way.

• To overcome stale element exception, you can re-locate the elem...read more

XPath code for selected value in Amazon site

• Use the 'contains' function to locate the selected value

• Identify the unique attributes of the selected value to create a specific XPath

• Consider using the 'text()' function to locate text within an element

APIs can be categorized into different types such as REST, SOAP, GraphQL, and RPC.

• RESTful APIs: Representational State Transfer APIs use standard HTTP methods like GET, POST, PUT, DELETE for communication.

• SOAP APIs: Simple Object Access Protocol APIs use XML for message exchange over a network.

• GraphQL APIs: Query language for APIs that allows clients to request only the data they need.

• RPC APIs: Remote Procedure Call APIs allow a program to execute code on a remote server.

Traversal of graphs involves visiting each vertex and edge in a graph in a systematic way.

• Traversal can be done using algorithms like Depth First Search (DFS) or Breadth First Search (BFS).

• DFS explores as far as possible along each branch before backtracking, while BFS explores neighbors before moving on.

• Traversal can be used to find paths, cycles, connected components, or perform other graph operations.

• Example: Traversing a social network graph to find friends of friends.

• Exa...read more

This task involves finding the second most frequently occurring letter in a given string, considering case sensitivity.

• Count Occurrences: Use a dictionary to count how many times each letter appears in the string. For example, in 'hello', 'l' appears twice.

• Sort by Frequency: Once you have the counts, sort the letters based on their frequency in descending order.

• Identify Second Highest: After sorting, the second item in the sorted list will be the second highest occurring lett...read more

Yes, I am involved in test plans.

• I collaborate with the team to create and review test plans.

• I ensure that the test plans cover all the necessary scenarios.

• I update the test plans as needed based on changes in requirements or functionality.

• I use the test plans to guide my testing efforts and report any issues found.

Java constructor is a special type of method used to initialize objects. Swapping two numbers can be done using a temporary variable.

• Java constructor is used to initialize objects in a class.

• Swapping two numbers can be done by using a temporary variable.

• Example code for swapping two numbers using constructor:

• public class NumberSwapper {

• int num1;

• int num2;

• public NumberSwapper(int a, int b) {

• num1 = a;

• num2 = b;

• }

• public void swapNumbers() {

• int temp = num1;

• num1 = num2;

• num2...read more

Program to find duplicate elements in an array of strings

• Create a HashSet to store unique elements

• Iterate through the array and check if element is already in the HashSet

• If element is already in the HashSet, it is a duplicate

Validating API through Postman involves sending requests, receiving responses, and verifying data.

• Create a new request in Postman and enter the API endpoint

• Add any required headers, parameters, or body data

• Send the request and check the response status code

• Verify the response body for expected data or values

• Use assertions in Postman to validate response data

• Save the request in a collection for future testing

Different types of testing include functional testing, non-functional testing, manual testing, automated testing, regression testing, and performance testing.

• Functional testing: Testing the functionality of the software against the requirements.

• Non-functional testing: Testing aspects like performance, usability, and security.

• Manual testing: Testing performed manually by testers.

• Automated testing: Testing performed using automation tools.

• Regression testing: Testing to ensure t...read more

Design patterns are reusable solutions to common software design problems, categorized into creational, structural, and behavioral patterns.

• Creational Patterns: Deal with object creation mechanisms. Example: Singleton, Factory Method.

• Structural Patterns: Focus on how classes and objects are composed. Example: Adapter, Composite.

• Behavioral Patterns: Concerned with communication between objects. Example: Observer, Strategy.

The occurrence of a character in a string refers to how many times that character appears within the string.

• Use the string method count() in Python: 'hello'.count('l') returns 2.

• In Java, use a loop to iterate through the string and count occurrences.

• Regular expressions can also be used to find occurrences: re.findall('l', 'hello') returns ['l', 'l'].

Some common exceptions in Selenium include NoSuchElementException, TimeoutException, StaleElementReferenceException, and ElementNotVisibleException.

• NoSuchElementException occurs when an element could not be found in the DOM.

• TimeoutException occurs when a command does not complete in the specified time.

• StaleElementReferenceException occurs when an element is no longer attached to the DOM.

• ElementNotVisibleException occurs when an element is present in the DOM but not visible on...read more

Java program to convert first letter of each word to upper case

• Split the input string into an array of words

• Iterate through each word and capitalize the first letter

• Join the words back together into a single string

Java program to remove duplicate characters from a string

• Create a HashSet to store unique characters

• Iterate through the string and add each character to the HashSet

• Construct a new string by appending characters from the HashSet

I have used interfaces in my project to achieve abstraction and decoupling of components.

• Used interfaces to define a contract for classes to implement

• Implemented interfaces to provide a common set of methods for different classes

• Utilized interfaces to enable polymorphism and dependency injection

Selenium automates web applications for testing purposes, ensuring functionality and performance across browsers.

• Use Selenium WebDriver to interact with web elements, e.g., driver.findElement(By.id('username')).sendKeys('testUser');

• Implement waits to handle dynamic content, e.g., WebDriverWait wait = new WebDriverWait(driver, 10); wait.until(ExpectedConditions.visibilityOfElementLocated(By.id('submit')));

• Utilize Page Object Model (POM) for better test organization, e.g., crea...read more

Creating and using class instances in Python for automation testing.

• Define a class using the 'class' keyword. Example: 'class MyClass:'.

• Create an instance of the class by calling it. Example: 'my_instance = MyClass()'.

• Access class attributes and methods using the instance. Example: 'my_instance.method_name()'.

• Use '__init__' method for initializing instance variables. Example: 'def __init__(self, value): self.value = value'.

• Instances can have unique states. Example: 'instance1...read more

Java program to count characters in a given string

• Use a HashMap to store characters and their counts

• Iterate through the string and update the counts in the HashMap

• Print the characters and their counts at the end