Vaisesika Consulting Senior ETL Tester Interview Questions and Answers

You can use a temporary table to change datatype without altering the original table.

• Create a new temporary table with the desired datatype

• Insert data from the original table into the temporary table

• Drop the original table

• Rename the temporary table to the original table name

Inner join returns only the matching rows between two tables, while left join returns all rows from the left table and the matching rows from the right table.

• Inner join result: 1 2 3

• Left join result: 1 2 3, 4 5 6, 7 8 9

Some tools used for ETL testing include Informatica PowerCenter, Talend, IBM InfoSphere DataStage, and Apache Nifi.

• Informatica PowerCenter

• Talend

• IBM InfoSphere DataStage

• Apache Nifi

Defect life cycle is the process of identifying, reporting, fixing, retesting, and closing defects in software development.

• Defect identification: Defects are identified through testing or user feedback.

• Defect reporting: Defects are reported in a defect tracking tool with details like steps to reproduce, severity, and priority.

• Defect fixing: Developers fix the reported defects based on the information provided.

• Defect re...read more

Black box testing focuses on functionality without knowledge of internal code, while white box testing examines internal code structure.

• Black box testing tests the functionality of a system without knowledge of its internal code

• White box testing tests the internal code structure and logic of a system

• Black box testing is more focused on end-user perspective

• White box testing is more focused on developer perspective

• Exampl...read more

Hard assert stops the execution of the test case if it fails, while soft assert continues the execution and logs the failure.

• Hard assert is used when the failure of a particular step makes the further steps irrelevant.

• Soft assert is used when you want to continue with the test case execution even if some steps fail.

• Hard assert is implemented using 'assert' keyword in testing frameworks like TestNG or JUnit.

• Soft assert ...read more

Annotations in Selenium WebDriver are used to provide additional information about the test methods.

• Annotations help in organizing and managing test cases

• Some common annotations in Selenium WebDriver are @Test, @BeforeTest, @AfterTest, @BeforeClass, @AfterClass, @BeforeMethod, @AfterMethod

• Annotations are used to define the sequence of execution of test methods

Use XPath to count the number of links with the text 'selenium'

• Use XPath to locate all the links containing the text 'selenium'

• Count the number of links found using the XPath expression

Use SQL query to display 60 pass and 40 fail from a table of students.

• Use SELECT statement with COUNT function to count the number of pass and fail statuses.

• Use WHERE clause to filter out pass and fail statuses.

• Use GROUP BY clause to group the statuses together.

• Use CASE statement to display the count of pass and fail statuses.

I have worked on various projects involving test automation for web applications using Selenium and API testing using Postman.

• Developed automated test scripts using Selenium WebDriver for regression testing of web applications

• Created test suites and executed test cases using TestNG framework

• Performed API testing using Postman to validate response data and status codes

• Integrated test automation scripts with CI/CD pipeli...read more

API testing is a type of software testing that involves testing APIs directly to ensure they meet functionality, reliability, performance, and security requirements.

• API testing involves testing the functionality, reliability, performance, and security of APIs.

• It focuses on verifying the communication and data exchange between different software systems.

• API testing can be done at different levels such as unit testing, i...read more

Post is used to create a new resource, while patch is used to update an existing resource.

• Post is used to create a new resource in the server.

• Patch is used to update an existing resource in the server.

• Post request typically includes all the data needed to create the resource, while patch request only includes the data that needs to be updated.

• Post requests are idempotent, meaning multiple identical requests will have t...read more

Priority and severity are used to classify the impact and importance of a defect in software testing.

• Priority determines the order in which defects should be fixed, based on business needs.

• Severity indicates the impact of a defect on the system or users.

• Priority is usually set by the product owner or business stakeholders.

• Severity is typically determined by the testing team based on the impact on functionality.

• Examples...read more

Project architecture refers to the overall structure of a software project, including components, modules, and their interactions.

• Project architecture defines how different components of a software project are organized and interact with each other.

• It includes the high-level design of the system, such as the database structure, data flow, and integration points.

• Project architecture also involves decisions on technologi...read more

Challenges in ETL testing include data quality issues, complex transformations, and handling large volumes of data.

• Data quality issues such as missing or incorrect data can impact testing results

• Complex transformations can be difficult to validate and may lead to errors in the ETL process

• Handling large volumes of data can slow down testing processes and require efficient testing strategies

Roles and responsibilities refer to the tasks and duties assigned to an individual within a specific job or position.

• Roles define the position or job title of an individual within an organization.

• Responsibilities outline the specific tasks, duties, and expectations associated with that role.

• Roles and responsibilities help clarify expectations, define boundaries, and ensure accountability.

• Examples include testing data e...read more

Use a dictionary to find duplicate values in an array of strings in Python.

• Create an empty dictionary to store the count of each string in the array.

• Iterate through the array and for each string, check if it exists in the dictionary. If it does, increment the count. If not, add it to the dictionary with a count of 1.

• After iterating through the array, check the dictionary for any strings with a count greater than 1. The

A deferred bug is a bug that is not fixed immediately but is scheduled to be fixed in a future release.

• Deferred bugs are usually lower priority bugs that do not impact the core functionality of the system.

• These bugs are documented and tracked for resolution in a later release.

• Examples of deferred bugs include cosmetic issues, minor usability problems, or non-critical functionality issues.

Use SQL query with ORDER BY and LIMIT to get 4th highest row based on a column

• Use ORDER BY clause to sort the column in descending order

• Use LIMIT 1 OFFSET 3 to get the 4th highest row

• Example: SELECT * FROM table_name ORDER BY column_name DESC LIMIT 1 OFFSET 3

Performance testing is a type of testing to ensure software applications perform well under expected workload.

• Performance testing evaluates the speed, responsiveness, and stability of an application under various load conditions.

• It helps identify bottlenecks, performance issues, and areas for improvement in the application.

• Types of performance testing include load testing, stress testing, and scalability testing.

• Tools ...read more

Correlation is a statistical measure that describes the strength and direction of a relationship between two variables.

• Correlation values range from -1 to 1, with 0 indicating no correlation, 1 indicating a perfect positive correlation, and -1 indicating a perfect negative correlation.

• Positive correlation means that as one variable increases, the other variable also increases. Negative correlation means that as one var...read more