Here is a list of common Manual Testing interview questions that cover various aspects of testing:
Basic Questions:
- What is Manual Testing?
- Explain the process of testing software manually without the use of automation tools.
- What are the different types of software testing?
- Discuss functional, non-functional, unit, integration, system, acceptance, smoke, sanity, regression, and usability testing.
- What is the difference between Verification and Validation?
- Verification: Checking if the product is designed as per the requirements.
- Validation: Ensuring the product functions as expected.
- What is a Test Case?
- Explain that it is a document that describes an input, action, or event to test a function of the software.
- What is a Test Plan?
- A detailed document that outlines the testing strategy, objectives, schedule, resources, and deliverables for a project.
- What is a Defect or Bug?
- A flaw in software that causes the program to behave unexpectedly.
- What are the key components of a Bug Report?
- ID, title, environment, steps to reproduce, actual result, expected result, severity, priority, and status.
- What is the difference between Severity and Priority?
- Severity: Impact of a defect on the functionality.
- Priority: Urgency to fix the defect.
- What is Exploratory Testing?
- Testing without specific test cases; learning the system while testing.
- What is Regression Testing?
- Testing to ensure that new code changes have not adversely affected the existing functionality.
Intermediate Questions:
- What is the Software Development Life Cycle (SDLC)?
- Discuss the phases such as requirements, design, development, testing, deployment, and maintenance.
- What is the Software Testing Life Cycle (STLC)?
- Phases include requirement analysis, test planning, test case development, environment setup, test execution, and test closure.
- What is the difference between Functional and Non-functional Testing?
- Functional Testing: Validates that software works as per the functional requirements.
- Non-functional Testing: Tests performance, scalability, usability, etc.
- What is the difference between Smoke and Sanity Testing?
- Smoke Testing: Performed to check whether the major functions of the software are working.
- Sanity Testing: Performed to check whether minor changes in code work properly.
- What is Boundary Value Analysis (BVA)?
- Testing technique that involves testing at the boundaries between partitions.
- What is Equivalence Partitioning?
- A technique that divides input data into equivalent partitions to reduce the number of test cases.
- What are Test Artifacts?
- Test Plan, Test Case, Test Script, Traceability Matrix, and Defect Report.
- What is the difference between White Box Testing and Black Box Testing?
- White Box: Testing internal structures or workings.
- Black Box: Testing functionality without knowing internal code.
- What is Ad-hoc Testing?
- Informal testing conducted without planning or documentation.
- What are Test Metrics?
- Test metrics like defect density, defect leakage, test coverage, and test execution status are used to measure the effectiveness of testing.
Advanced Questions:
- How do you handle changes in requirements during the testing process?
- Discuss how to update test cases, re-plan, and communicate with the team about the changes.
- What is Test Coverage and how do you ensure it?
- It measures the extent to which testing covers the product’s functionality. Achieved through traceability matrices and thorough test case design.
- What is Defect Leakage and how do you prevent it?
- Defect leakage occurs when defects are missed during testing and are found in production. Prevent it by increasing test coverage and including regression testing.
- How do you prioritize test cases in Manual Testing?
- Discuss criteria such as business impact, risk, critical functionalities, and the complexity of test cases.
- What are Entry and Exit Criteria in testing?
- Entry Criteria: Conditions that must be met before testing begins.
- Exit Criteria: Conditions that must be met before testing is concluded.
- How do you ensure that a defect is reproducible?
- By providing clear steps to reproduce the defect, attaching screenshots/logs, and verifying the environment.
- What is Cross-browser Testing?
- Testing a website or application across multiple browsers to ensure consistent behavior and functionality.
- What are the common challenges faced during Manual Testing?
- Challenges like time constraints, incomplete requirements, lack of test data, and handling frequent changes.
- What is a Traceability Matrix?
- A document that traces and maps user requirements with test cases to ensure all requirements are tested.
- How do you handle testing in an Agile environment?
- Discuss continuous testing, collaboration with developers, frequent releases, and maintaining test coverage through sprints.
Scenario-based Questions:
- How would you approach testing if you don’t have any documentation?
- Explore exploratory testing, interviewing stakeholders, and gaining a deep understanding of the application.
- How would you test a login page?
- Test positive and negative cases, boundary values, session management, security (SQL injection, brute force), and UI validations.
- How do you deal with conflicts between testers and developers?
- Focus on collaboration, clear communication, and problem-solving without focusing on blame.
- How do you handle a situation where a bug is not reproducible?
- Re-check the environment, review steps, use logs/screenshots, and collaborate with developers for root cause analysis.
- How do you manage a team of testers with different experience levels?
- Discuss your approach to mentoring juniors, delegating tasks based on experience, and fostering collaboration among team members.
- How do you handle conflicts within your team?
- Explain conflict resolution strategies, focusing on communication, mediation, and maintaining a positive team environment.
- How do you ensure that your team meets project deadlines?
- Mention task prioritization, proper resource allocation, clear communication, regular status meetings, and risk management.
- How do you motivate your testing team?
- Talk about recognizing achievements, providing growth opportunities, offering constructive feedback, and setting clear, attainable goals.
- How do you manage remote or distributed testing teams?
- Discuss using collaboration tools, maintaining regular communication, and setting clear expectations for remote work.
- What is your approach to training and developing your team members?
- Focus on skill assessments, creating learning plans, encouraging certifications, and arranging internal or external training.
Project and Test Management:
- What is your approach to creating a Test Plan?
- Include test objectives, scope, test strategy, resources, schedule, test deliverables, risks, and contingencies.
- How do you handle changes in requirements during testing?
- Explain how you manage scope changes by revising test cases, updating the test plan, communicating with stakeholders, and reprioritizing tasks.
- How do you manage test resources across multiple projects?
- Talk about resource planning, workload balancing, cross-training, and assigning testers based on their skill sets.
- What steps do you take to improve test coverage?
- Focus on using traceability matrices, reviewing requirements, improving test case design, and conducting risk-based testing.
- What strategies do you use for risk management in testing?
- Explain how you identify risks early, assess their impact and likelihood, and develop mitigation plans such as prioritizing high-risk areas.
- How do you handle incomplete requirements during the testing phase?
- Discuss engaging with stakeholders for clarification, applying exploratory testing, and developing a test strategy based on assumptions.
- What are Entry and Exit Criteria?
- Explain the importance of defining clear conditions for starting and stopping testing based on the quality of the product and meeting defined goals.
- What test metrics do you track as a Test Lead?
- Mention key metrics like defect density, test case execution rate, test coverage, defect leakage, test effort, and defect closure rate.
- How do you prioritize testing tasks in a time-constrained project?
- Focus on risk-based testing, prioritizing critical functionalities, and working with the development team to identify key areas for testing.
- How do you ensure effective communication between your team and other departments?
- Talk about regular meetings, transparent status reports, issue tracking tools, and maintaining open communication channels.
Process Improvement:
- What steps have you taken to improve the testing process in your previous roles?
- Share specific examples, such as implementing automation, refining test cases, reducing defects, or improving collaboration between teams.
- How do you handle underperforming team members?
- Explain your approach to providing constructive feedback, setting performance improvement plans, and offering support or training.
- How do you stay updated with the latest trends and tools in testing?
- Mention attending conferences, reading industry blogs, taking certifications, or encouraging your team to share knowledge.
- How do you measure the success of your testing efforts?
- Discuss using metrics like defect density, customer satisfaction, test case effectiveness, and post-release defect counts.
- What tools do you use for Test Management, and why?
- Name tools like JIRA, TestRail, HP ALM, or Zephyr, and explain how they help manage test cases, defects, and reporting.
Technical Knowledge and Problem-Solving:
- How do you ensure the quality of testing in an Agile environment?
- Talk about integrating continuous testing, collaborating closely with developers, using automation, and ensuring high test coverage within sprints.
- How do you approach Regression Testing?
- Explain strategies for identifying the areas most at risk of regression, automating key test cases, and managing regression test suites.
- What is your approach to handling large-scale testing for enterprise applications?
- Mention organizing test cases, using automation where feasible, breaking down testing into phases, and focusing on high-priority areas.
- How do you ensure that non-functional testing (e.g., performance, security) is included in the testing process?
- Discuss involving performance and security testing from the start, defining non-functional requirements, and collaborating with the right teams.
- What is your approach to handling a situation where a critical defect is discovered late in the release cycle?
- Focus on assessing the impact, working with stakeholders to determine the best course of action, and prioritizing a hotfix if necessary.
- What is the most complex project you’ve led as a Test Lead, and how did you handle it?
- Share a case study involving challenges like tight deadlines, complex requirements, or large teams, and explain how you overcame them.
- How do you approach test automation as a Test Lead?
- Discuss where automation fits in the testing strategy, how you choose tools, and the balance between manual and automated testing.
- How do you manage cross-browser and cross-platform testing?
- Explain the use of tools like Selenium, BrowserStack, or LambdaTest, and discuss defining coverage based on the target audience.
- How do you approach testing in a DevOps or CI/CD pipeline?
- Discuss implementing continuous testing, automating test cases, using tools like Jenkins, and ensuring quick feedback loops for developers.
- What role do test environments play, and how do you ensure their availability and stability?
- Discuss planning for test environments, coordinating with IT teams, managing data, and ensuring that environments mirror production as closely as possible.
Scenario-Based Questions:
- If your team finds a critical bug just before the release, what steps will you take?
- Talk about assessing the bug’s impact, prioritizing a fix, engaging stakeholders, and determining whether to delay the release or provide a workaround.
- How do you handle a situation where developers reject a valid defect reported by your team?
- Mention presenting evidence (logs, screenshots), escalating when necessary, and maintaining a collaborative attitude to resolve the issue.
- How do you handle test case reviews?
- Explain the importance of peer reviews, ensuring that all scenarios are covered, and following a checklist for test case quality.
- What would you do if the development team insists on delivering a feature without sufficient testing time?
- Discuss negotiating for more testing time, identifying high-risk areas, and using exploratory testing to cover the most critical functions.
- How do you manage stakeholder expectations when there are project delays due to testing issues?
- Talk about transparency, communicating issues early, offering data to support the delay, and discussing mitigation strategies.
When attending a Test Engineer interview that focuses on real-time project scenarios, the questions tend to be practical and scenario-based. Below are some common real-time Manual and Automation Testing interview questions along with possible areas to focus on:
Project and Role-Specific Questions:
- Describe your most recent testing project. What was your role?
- Discuss your role in the project, the product you tested, the testing methodologies you used, the size of the team, and the tools you worked with.
- What were the key challenges you faced in your last testing project, and how did you overcome them?
- Be prepared to talk about issues like tight deadlines, changing requirements, environment issues, or dealing with complex functionalities.
- How did you contribute to improving the quality of the software in your last project?
- Mention specific actions like improving test cases, finding critical defects, creating better documentation, or advocating for automation.
- Can you walk us through a critical defect you found during testing in a recent project?
- Explain the context, steps to reproduce, why it was critical, how it was resolved, and the impact on the project.
- How do you manage test data in real-time projects?
- Discuss how you set up, maintain, and manage test data, especially for different environments like QA, UAT, and production. Mention tools or methods used (e.g., database seeding, mocks, or stubs).
- How do you handle situations where requirements are unclear or incomplete?
- Talk about how you collaborate with stakeholders, conduct exploratory testing, or make assumptions based on experience to create useful test cases.
Test Planning and Execution:
- How do you approach writing test cases for a new feature?
- Discuss understanding requirements, breaking down the feature into testable components, writing positive and negative test cases, boundary value analysis, and ensuring full coverage.
- What testing strategies do you use for high-risk areas in a project?
- Mention prioritization of testing critical modules first, risk-based testing, focusing on edge cases, and involving both functional and non-functional testing.
- Describe how you performed regression testing in your last project.
- Explain how you identified the impact areas, how frequently regression tests were executed, and whether you used automation to speed up the process.
- How do you ensure test coverage in your projects?
- Discuss methods like traceability matrices, reviewing requirements, and ensuring that each functional requirement has a corresponding test case.
- How do you handle testing when timelines are very tight?
- Focus on strategies like risk-based testing, executing the most critical test cases, performing exploratory testing, and negotiating timelines with stakeholders.
Bug Tracking and Defect Management:
- What was the most difficult defect you encountered, and how did you debug it?
- Be prepared to describe a complex bug, how you tracked down the root cause, and how it was eventually fixed.
- What is the process you follow to report a defect?
- Discuss defect reporting tools (e.g., JIRA, Bugzilla), how you log defects (including steps to reproduce, severity, priority, environment, etc.), and communication with developers.
- How do you decide the priority and severity of a bug?
- Explain how you assess the business impact (priority) and technical impact (severity) of defects, providing real examples.
- Have you encountered a situation where a bug was not reproducible? How did you handle it?
- Mention steps like recreating the same environment, reviewing logs, discussing with the development team, or using monitoring tools to gather more information.
- How do you handle bugs that are marked as ‘Won’t Fix’ by the development team?
- Discuss how you ensure the bug’s impact is well understood, escalate the issue if necessary, and communicate back to the stakeholders or business team.
Testing Methodologies and Best Practices:
- What testing methodologies have you used in your projects?
- Discuss methodologies like Agile, Waterfall, Scrum, or Kanban, and explain how they influenced your testing activities.
- How do you differentiate between smoke testing and sanity testing in your project?
- Provide examples of when you conducted smoke and sanity tests, focusing on the goals of each type of testing.
- What is the difference between functional and non-functional testing, and how did you handle them in your project?
- Explain functional testing (validating that the software works according to requirements) and non-functional testing (performance, security, usability, etc.).
- How did you approach performance testing in your last project?
- Discuss tools like JMeter, LoadRunner, or similar, the metrics you focused on (response time, throughput, etc.), and how you analyzed and reported the results.
- How do you ensure cross-browser and cross-device compatibility in your testing?
- Mention tools (e.g., BrowserStack, Sauce Labs) and how you validate UI/UX and functionality across different browsers and devices.
Automation Testing Questions:
- Have you automated any tests in your projects? If so, which ones and why?
- Mention the specific tests (e.g., regression, smoke) that were automated and the tools used (e.g., Selenium, TestNG, Cypress, etc.). Also, explain why automation was important for your project.
- How do you decide which test cases should be automated and which should remain manual?
- Talk about prioritizing test cases that are repetitive, time-consuming, and critical for automation while keeping exploratory and ad-hoc tests manual.
- Can you describe a challenging scenario where you implemented automation in a real-time project?
- Provide details about the automation framework you used, challenges faced (like dynamic elements, large datasets), and how you overcame those.
- How do you integrate automated tests in a CI/CD pipeline?
- Explain how automated tests fit into the build and deployment pipeline, tools you use (e.g., Jenkins, Bamboo), and how you handle test failures.
- How do you handle flaky tests in automation?
- Discuss identifying flaky tests, reasons for flakiness (e.g., timing issues, inconsistent environments), and how you resolved them by stabilizing the tests.
Agile and Continuous Testing:
- How do you handle testing in an Agile project?
- Talk about working closely with developers, conducting testing within sprints, participating in daily stand-ups, and maintaining an automated test suite.
- How do you manage frequent releases in a continuous delivery environment?
- Discuss regression automation, working in parallel with development, running tests as part of every build, and using CI/CD tools for continuous testing.
- What challenges have you faced while testing in Agile?
- Mention challenges like short sprint cycles, evolving requirements, and balancing manual and automated testing efforts.
- How do you collaborate with developers and product managers in Agile testing?
- Focus on communication, early involvement in planning, refining user stories, and providing continuous feedback.
- How do you ensure the quality of software in a fast-paced Agile environment?
- Mention continuous testing, test automation, test coverage strategies, and maintaining a tight feedback loop between development and testing.
Real-time Problem Solving and Scenarios:
- You’re testing a web application, and suddenly the database crashes. How do you proceed?
- Explain the importance of proper error handling, logging, and collaboration with the database and infrastructure teams. Mention checking backups, logs, and system resilience.
- A feature is set to release tomorrow, and you’ve discovered a critical defect. What steps do you take?
- Talk about escalating the issue, prioritizing the defect, discussing with stakeholders, and suggesting possible alternatives (e.g., delaying the release or providing a hotfix).
- What would you do if you had only one day left to test a feature that is part of the release?
- Focus on risk-based testing, prioritizing critical test cases, using exploratory testing, and performing smoke tests to ensure major functionalities work.
- How do you handle a situation where your team finds new bugs at the last minute before release?
- Talk about assessing the severity, communicating with the project manager, and deciding on delaying the release or proceeding with known issues based on business priorities.
- You have a tight deadline, and your test suite has thousands of test cases. How do you optimize your testing effort?
- Discuss test prioritization, focusing on critical paths, using automation for regression, and conducting exploratory testing for new features.
By preparing for these real-time project scenario-based questions, you’ll be able to demonstrate your hands-on experience, technical knowledge, and ability to handle challenges in real-world testing environments.
Here are some common Linux interview questions for Test Engineers that cover key topics like basic commands, shell scripting, file management, permissions, and troubleshooting:
Basic Linux Commands:
- What is the command to view all the files and directories in Linux, including hidden files?
- Command: ls -a
- How do you check the current working directory?
- Command: pwd (Print Working Directory)
- What is the command to create a new directory in Linux?
- Command: mkdir <directory_name>
- How do you copy files from one directory to another in Linux?
- Command: cp <source_file> <destination_directory>
- How do you move or rename a file in Linux?
- Command: mv <source_file> <destination> (Used for both renaming and moving files)
- How can you display the contents of a file in Linux?
- Commands: cat <file_name>, less <file_name>, or more <file_name>
- How do you delete a file or directory in Linux?
- To delete a file: rm <file_name>
- To delete a directory: rm -r <directory_name>
- How do you find a specific word in a file in Linux?
- Command: grep <word> <file_name>
- How do you check the disk usage of files and directories in Linux?
- Command: du -h (shows disk usage in human-readable format)
- How can you check the available disk space on your system?
- Command: df -h
File Permissions and Ownership:
- How do you check the permissions of a file in Linux?
- Command: ls -l (Shows the permissions of files and directories)
- What command is used to change the file permissions in Linux?
- Command: chmod <permissions> <file_name> (e.g., chmod 755 file.sh)
- What are the permission symbols in Linux, and what do they represent?
- r: Read permission
- w: Write permission
- x: Execute permission
- How do you change the owner of a file in Linux?
- Command: chown <new_owner> <file_name>
- What is the command to change the group ownership of a file?
- Command: chgrp <group_name> <file_name>
- What is the numeric representation of file permissions in Linux?
- Permissions are represented as a three-digit number. For example:
- 777: Full permissions (rwx for user, group, others)
- 755: Read and execute for group and others, full permission for the owner
- 644: Read and write for the owner, read-only for group and others
- Permissions are represented as a three-digit number. For example:
- How can you recursively change the permissions of all files within a directory?
- Command: chmod -R <permissions> <directory_name>
Process Management and Monitoring:
- How do you view currently running processes in Linux?
- Command: ps or top (real-time view of processes)
- What is the command to kill a process in Linux?
- Command: kill <process_id> or kill -9 <process_id> for a forceful kill
- How do you find the process ID (PID) of a running program?
- Command: ps aux | grep <process_name>
- What is the difference between kill and kill -9?
- kill sends a SIGTERM signal, allowing the process to terminate gracefully.
- kill -9 sends a SIGKILL signal, which forces the process to terminate immediately.
- How do you check the system’s memory usage in Linux?
- Command: free -h
- How can you check CPU usage for processes in Linux?
- Command: top or htop (if installed)
Networking Commands:
- How do you check the IP address of your system?
- Command: ifconfig or ip addr
- How do you check if a server is reachable in Linux?
- Command: ping <hostname or IP_address>
- How do you check network connections or listening ports in Linux?
- Command: netstat -an or ss -tuln
- How do you check which services are running on specific ports?
- Command: netstat -tuln or ss -tuln
- How do you establish an SSH connection to a remote server?
- Command: ssh user@hostname_or_IP
- How do you transfer files between two Linux systems?
- Command: scp <file_name> user@remote_host:/path/to/destination
Shell Scripting:
- What is a shell script?
- A shell script is a text file that contains a series of commands to be executed by the shell.
- How do you make a shell script executable?
- Command: chmod +x <script_name>
- How do you execute a shell script?
- Command: ./<script_name>
- How do you declare a variable in a shell script?
- Example: variable_name=”value”
- How do you read input from a user in a shell script?
- Example: read variable_name
- How do you write an if condition in a shell script?
bash
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if [ condition ]
then
# Commands to be executed if the condition is true
else
# Commands to be executed if the condition is false
fi
- How do you write a for loop in a shell script?
bash
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for i in {1..5}
do
echo “Iteration $i”
done
- What is the purpose of exit in shell scripting?
- exit is used to terminate a script and return an exit status to the calling process. Example: exit 0 indicates success.
- How do you redirect output to a file in a shell script?
- Command: command > output_file (overwrites) or command >> output_file (appends)
- How do you check the exit status of a command in a shell script?
- Command: echo $? (returns 0 for success, non-zero for failure)
File Compression and Archiving:
- How do you create a compressed archive file in Linux?
- Command: tar -czvf archive_name.tar.gz <directory_or_file>
- How do you extract a .tar.gz file in Linux?
- Command: tar -xzvf archive_name.tar.gz
- How do you list the contents of a .tar.gz file without extracting it?
- Command: tar -tzvf archive_name.tar.gz
Log Management and Troubleshooting:
- How do you view system logs in Linux?
- Command: tail -f /var/log/syslog or tail -f /var/log/messages (depending on the distribution)
- How do you search for a specific string in log files?
- Command: grep <search_string> /var/log/syslog
- How do you view the last 100 lines of a log file?
- Command: tail -n 100 <log_file>
- How do you monitor a log file in real-time?
- Command: tail -f <log_file>
- What is the command to check if a service is running?
- Command: systemctl status <service_name>
- How do you restart a service in Linux?
- Command: systemctl restart <service_name>
Advanced Topics:
- What is the difference between cron and at?
- cron is used for scheduling repetitive tasks, while at is used for scheduling one-time tasks.
- How do you schedule a cron job in Linux?
- Command: crontab -e to edit the cron jobs.
- Syntax: minute hour day_of_month month day_of_week command
- How do you view the cron jobs of a specific user?
- Command: crontab -l -u <user>
- What is the purpose of the /etc/fstab file?
- The /etc/fstab file defines how disk partitions, filesystems, and other devices are mounted.
By preparing for these Linux questions, you’ll be well-equipped to handle real-world scenarios that you may encounter as a Test Engineer.
Here are some common SQL interview questions for Test Engineers that cover key topics like querying, joins, indexes, performance optimization, and database testing:
Basic SQL Queries:
- What is SQL, and what are its types?
- SQL (Structured Query Language) is used to interact with databases. The main types of SQL commands are:
- DDL (Data Definition Language): CREATE, ALTER, DROP
- DML (Data Manipulation Language): INSERT, UPDATE, DELETE, SELECT
- DCL (Data Control Language): GRANT, REVOKE
- TCL (Transaction Control Language): COMMIT, ROLLBACK, SAVEPOINT
- SQL (Structured Query Language) is used to interact with databases. The main types of SQL commands are:
- How do you fetch all the records from a table?
- Query: SELECT * FROM <table_name>;
- How do you retrieve only the distinct values from a column in SQL?
- Query: SELECT DISTINCT column_name FROM <table_name>;
- How do you sort the records in a table in ascending or descending order?
- Query (ascending order): SELECT * FROM <table_name> ORDER BY column_name ASC;
- Query (descending order): SELECT * FROM <table_name> ORDER BY column_name DESC;
- How do you filter records based on a condition?
- Query: SELECT * FROM <table_name> WHERE condition;
- What is the difference between WHERE and HAVING clauses?
- WHERE is used to filter records before any aggregation.
- HAVING is used to filter records after aggregation, typically used with GROUP BY.
- How do you retrieve the top 5 records from a table?
- Query in MySQL: SELECT * FROM <table_name> LIMIT 5;
- Query in SQL Server: SELECT TOP 5 * FROM <table_name>;
- How do you find records that match a specific pattern in a column?
- Query: SELECT * FROM <table_name> WHERE column_name LIKE ‘pattern’;
- Example: SELECT * FROM Employees WHERE FirstName LIKE ‘J%’; (finds all names starting with ‘J’).
- How do you find the number of records in a table?
- Query: SELECT COUNT(*) FROM <table_name>;
- How do you find the maximum or minimum value in a column?
- Query (maximum): SELECT MAX(column_name) FROM <table_name>;
- Query (minimum): SELECT MIN(column_name) FROM <table_name>;
Joins in SQL:
- What is a JOIN in SQL?
- A JOIN clause is used to combine rows from two or more tables based on a related column between them.
- What are the different types of SQL JOINs?
- INNER JOIN: Returns only the records that have matching values in both tables.
- LEFT (OUTER) JOIN: Returns all records from the left table, and the matched records from the right table. If no match, NULL values are returned for columns from the right table.
- RIGHT (OUTER) JOIN: Returns all records from the right table, and the matched records from the left table.
- FULL (OUTER) JOIN: Returns all records when there is a match in either left or right table.
- Write a query to fetch records using an INNER JOIN.
sql
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SELECT A.column1, B.column2
FROM table1 A
INNER JOIN table2 B
ON A.id = B.id;
- Write a query to fetch records using a LEFT JOIN.
sql
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SELECT A.column1, B.column2
FROM table1 A
LEFT JOIN table2 B
ON A.id = B.id;
- What is a SELF JOIN?
- A SELF JOIN is a regular join but the table is joined with itself.
sql
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SELECT A.column1, B.column2
FROM table1 A, table1 B
WHERE A.id = B.id;
- What is a CROSS JOIN?
- A CROSS JOIN returns the Cartesian product of the two tables, meaning it combines all rows of the first table with all rows of the second table.
sql
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SELECT * FROM table1 CROSS JOIN table2;
SQL Functions and Aggregation:
- How do you calculate the sum of a column?
- Query: SELECT SUM(column_name) FROM <table_name>;
- How do you group records by a specific column and get aggregated results?
- Query: SELECT column_name, COUNT(*) FROM <table_name> GROUP BY column_name;
- What is the difference between COUNT(*) and COUNT(column_name)?
- COUNT(*) counts all rows, including those with NULL values.
- COUNT(column_name) counts only the rows where the column value is not NULL.
- How do you find the average value in a column?
- Query: SELECT AVG(column_name) FROM <table_name>;
- How do you concatenate two strings in SQL?
- Query (MySQL, SQL Server): SELECT CONCAT(string1, string2);
- What is the use of the GROUP BY clause?
- The GROUP BY clause is used to group rows that have the same values in specified columns into aggregated results like COUNT, SUM, AVG, etc.
Subqueries and Set Operations:
- What is a subquery in SQL?
- A subquery is a query within another query. The subquery can return a single value, a set of values, or even rows.
sql
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SELECT * FROM Employees
WHERE salary > (SELECT AVG(salary) FROM Employees);
- What is the difference between a correlated subquery and a non-correlated subquery?
- Correlated Subquery: Depends on the outer query. It is executed for each row in the outer query.
- Non-Correlated Subquery: Independent of the outer query and is executed once.
- What is the difference between UNION and UNION ALL?
- UNION removes duplicate records and combines the result sets.
- UNION ALL includes all records, including duplicates.
- How do you use EXISTS in a query?
- EXISTS checks whether the subquery returns any rows.
sql
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SELECT * FROM Employees
WHERE EXISTS (SELECT 1 FROM Departments WHERE Employees.dept_id = Departments.id);
- What is the IN operator in SQL?
- The IN operator allows you to specify multiple values in a WHERE clause.
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SELECT * FROM Employees WHERE department IN (‘HR’, ‘Finance’);
Indexes, Constraints, and Keys:
- What is an index in SQL?
- An index improves the speed of data retrieval operations on a table at the cost of slower INSERT and UPDATE operations.
- What are the types of indexes in SQL?
- Unique Index: Ensures all values in a column are unique.
- Composite Index: Created on more than one column to speed up queries.
- Clustered Index: Physically sorts the data in the table based on key values.
- Non-Clustered Index: Creates a logical order that doesn’t alter the physical order.
- What is a primary key?
- A primary key is a column (or a set of columns) that uniquely identifies each row in a table.
- What is a foreign key?
- A foreign key is a field in one table that refers to the primary key of another table to establish a relationship between the two tables.
- What is the difference between PRIMARY KEY and UNIQUE constraints?
- PRIMARY KEY ensures uniqueness and does not allow NULL values.
- UNIQUE also ensures uniqueness but allows NULL values (except in some databases like SQL Server).
- What is a composite key?
- A composite key is a combination of two or more columns used to uniquely identify a row in a table.
Database Testing and Performance:
- How do you validate data integrity during database testing?
- By using SQL queries to ensure the data matches expected values, constraints are enforced, and relationships between tables (via foreign keys) are valid.
- What steps do you take to ensure your SQL queries are optimized?
- Use EXPLAIN or EXPLAIN PLAN to understand query execution plans.
- Create indexes on columns used in WHERE, JOIN, or GROUP BY clauses.
- Avoid unnecessary columns in SELECT *, and write selective queries.
- Use proper indexing, minimize subqueries, and avoid heavy operations on large datasets.
- What is normalization, and why is it important?
- Normalization is the process of organizing data to reduce redundancy and dependency. It improves data integrity and reduces storage space.
Here are some common API Testing Interview Questions for Test Engineers, covering various aspects like REST, SOAP, tools, methods, and real-time scenarios:
Basic API Concepts:
- What is an API?
- An API (Application Programming Interface) is a set of protocols and tools that allows communication between two software applications.
- What is API testing?
- API testing involves testing the application interfaces directly to verify functionality, reliability, performance, and security. It primarily focuses on business logic and is usually done at the service layer.
- How does API testing differ from UI testing?
- API Testing checks the functionality of the backend (business logic) and communicates between applications via API calls, whereas UI Testing focuses on the graphical user interface.
- What are the main components of an HTTP request?
- HTTP Method: GET, POST, PUT, DELETE
- Endpoint/URL
- Headers: Information like Content-Type, Authorization, etc.
- Body: The payload sent in requests (usually in POST/PUT requests).
- Parameters: Query or path parameters.
- What are the most common HTTP methods used in RESTful APIs?
- GET: Retrieve data from the server.
- POST: Send data to the server to create a resource.
- PUT: Update an existing resource on the server.
- DELETE: Remove a resource from the server.
- PATCH: Partially update an existing resource.
- What is the difference between REST and SOAP APIs?
- REST is an architectural style that uses standard HTTP methods (GET, POST, etc.) and typically exchanges data using JSON or XML.
- SOAP is a protocol that uses XML-based messaging and requires more rigid structure and rules, including the use of WSDL (Web Services Description Language).
- What are the main differences between POST and PUT methods in API testing?
- POST is used to create new resources and is not idempotent (calling it multiple times may create duplicate resources).
- PUT is used to update existing resources and is idempotent (calling it multiple times will always update the same resource).
- What is idempotency in API testing?
- Idempotency means that the result of a successful operation is the same, no matter how many times it is performed. GET, PUT, and DELETE methods should ideally be idempotent.
- What are status codes in HTTP, and why are they important in API testing?
- Status codes are issued by a server in response to a client’s request. They indicate whether a request was successful, failed, or requires further action. Common ones include:
- 200 OK: Success
- 201 Created: Resource successfully created
- 400 Bad Request: Client-side error
- 401 Unauthorized: Authentication required
- 404 Not Found: Resource not found
- 500 Internal Server Error: Server-side error
- Status codes are issued by a server in response to a client’s request. They indicate whether a request was successful, failed, or requires further action. Common ones include:
Testing Techniques and Scenarios:
- How do you perform API testing?
- Identify the API endpoint to be tested.
- Verify the response by sending HTTP requests using tools like Postman, REST Assured, or JMeter.
- Validate the response body, headers, status code, and any other required data like authentication.
- Test negative scenarios to check how the API handles errors.
- Perform performance and security testing to ensure the API meets SLAs.
- What is a response time in API testing, and how do you measure it?
- Response time is the time taken by the API to respond to a request. It can be measured using tools like Postman, JMeter, or New Relic. Low response times indicate good performance.
- What are the common types of API testing?
- Functional Testing: Validating if the API works as expected.
- Load Testing: Checking how the API performs under high traffic.
- Security Testing: Ensuring the API is secure from vulnerabilities.
- Integration Testing: Ensuring that APIs interact well with other components.
- Validation Testing: Verifying the data format and values in responses.
- How do you handle authentication in API testing?
- Use appropriate authentication mechanisms like:
- Basic Authentication: Sending base64 encoded credentials.
- OAuth 2.0: Using access tokens.
- API Keys: Unique keys provided by the service provider.
- JWT (JSON Web Token): Using token-based authentication for stateless communication.
- Use appropriate authentication mechanisms like:
- How do you validate the response of an API?
- Check status codes: Ensure it matches expected status (e.g., 200 for success).
- Validate response body: Verify the format (JSON, XML) and key-value pairs.
- Check response headers: Ensure headers like Content-Type, Cache-Control, and Authorization are accurate.
- Schema validation: Ensure that the response adheres to the expected schema.
- What is a negative test case in API testing?
- Negative testing involves sending invalid inputs to verify how the API handles errors. Examples include:
- Sending wrong data types (e.g., string instead of integer).
- Omitting required fields.
- Sending unauthorized requests.
- Negative testing involves sending invalid inputs to verify how the API handles errors. Examples include:
- What are some common validation techniques used in API testing?
- Schema validation: Ensuring the response follows the correct structure (e.g., JSON schema).
- Field validation: Checking that fields contain valid data and correct data types.
- Boundary testing: Testing with edge-case inputs (e.g., max/min length for strings).
- Error codes and messages: Ensuring error codes and messages are informative and correct.
API Testing Tools:
- Which tools are commonly used for API testing?
- Postman: Popular tool for manual API testing, offering powerful features like collections and scripting.
- SoapUI: Used for both REST and SOAP web service testing.
- REST Assured: Java-based library for automating REST API testing.
- JMeter: Used for performance testing APIs.
- Karate: Another framework for API automation testing.
- What is Postman, and how do you use it for API testing?
- Postman is a tool used to send API requests and verify the response. You can create test suites, collections, and even automate requests with JavaScript in Postman.
- How do you automate API tests?
- Use tools like Postman, REST Assured, or Karate for automation.
- Write test scripts to send API requests, capture responses, and compare results against expected values.
- Integrate automated API tests into CI/CD pipelines using tools like Jenkins or GitLab CI.
- What is REST Assured?
- REST Assured is a Java-based library that simplifies REST API testing by providing a set of libraries to send HTTP requests and validate responses.
- How do you perform API performance testing using JMeter?
- In JMeter, create a test plan for your API.
- Add an HTTP Request Sampler for the API endpoint.
- Add Listeners (e.g., View Results Tree, Aggregate Report) to measure performance metrics.
- Run the test and check metrics like response time, throughput, and error rates.
Advanced API Testing Questions:
- How do you handle rate-limiting in API testing?
- Rate-limiting is a method used to control the number of API requests allowed in a certain time frame. In testing, simulate high traffic and ensure the API responds with a proper error code like 429 Too Many Requests when the limit is exceeded.
- What is API mocking, and why is it useful?
- API mocking is used to simulate API responses when the actual API is unavailable or under development. This is helpful in early stages of testing to ensure that dependent systems can be tested without waiting for the API to be fully functional.
- How do you test for API security vulnerabilities?
- Perform penetration testing on the API.
- Check for vulnerabilities like SQL Injection, Cross-Site Scripting (XSS), and Cross-Site Request Forgery (CSRF).
- Test if sensitive data (like tokens or credentials) is exposed.
- Ensure HTTPS is used for secure communication.
- What is an API gateway, and how does it affect testing?
- An API gateway is an entry point for all client requests to access backend services. It handles tasks like request routing, authentication, and rate-limiting. Test engineers need to ensure the gateway enforces security, routing rules, and rate limits.
- What is pagination in API testing, and how do you test it?
- Pagination is used to limit the number of results returned by an API at once (for large datasets). Test engineers validate that APIs return the correct results across pages and handle parameters like limit and offset properly.
- How do you test API versioning?
- Ensure backward compatibility by testing different API versions (e.g., /v1/, /v2/) and checking that new changes do not affect existing versions.
These questions should help in assessing the understanding and technical skills of test engineers during API testing interviews.
Soft Skills and Communication:
- How do you communicate test results to non-technical stakeholders?
- Mention using simplified language, focusing on business impact, and presenting clear visuals or metrics to explain the test outcomes.
- How do you handle pressure in a high-stakes project?
- Discuss staying organized, delegating tasks, focusing on critical areas, and maintaining open communication with the team and stakeholders.