What is JUnit?
JUnit is an open-source framework used by Java developers to run and write repeatable tests with the help of a unit testing framework for Java. This testing standard is quite an essential framework that every java developer must be familiar with. The knowledge of writing these tests are checked in the JUnit interview questions. This article provides you with the top 23 JUnit interview questions. These skills differentiate professional developers from amateur ones.
JUnit interview tips
Java Programming interviews check the familiarity of the developers with these top 23 JUnit interview questions. The ability to write these tests professionally helps a person to test their logic confidently and repeatedly. There are some basic and frequently asked JUnit interview questions in the interview process. To make sure you ace these JUnit interview questions, get a thorough recap of all these questions and the concepts of the testing method.
Here are some of the best JUnit interview questions and answers to help you prepare for the interview and leave a good impression on the interviewer with your knowledge and skills.
Frequently Asked JUnit Interview Questions:
1. What is JUnit?
JUnit is a testing framework used in Java programming to accelerate the testing process or the speed of your programming and check the quality of the code. It stands for Java + unit testing.
2. What is testing?
Testing is a process that helps to check the functionality of the application. It is used to check if the application is working according to the requirements or not.
3. What is a test suite?
A test suite is compiling a few test units and then running them together.
4. What is manual testing?
Manual testing is when the test cases are executed without the help or support of any tools.
5. What is automated testing?
Execution of the test cases with the help of automation tools is termed automated testing.
6. What are some disadvantages of manual testing?
Manual testing is done without the help of any tool and thus is very time consuming and tiring. In addition, this method is less reliable, and the testing cannot be programmed.
7. Tell us some advantages of automated testing.
Automated testing is done with the help of automation tools and thus is more reliable and fast. The testing from this method can be programmed.
8. Name a few JUnit extensions.
- JWebUnit
- XML unit
- Mock object
- Cactus
9. What is a unit test case?
A unit test case is used to test the code’s functionality and ensure that the method of the code is correct and works as expected.
10. Is it necessary to write a test case?
Test cases are written for logic that is broken. Therefore, it is not necessary to write a test case for every reason.
11. What is a test runner used for?
Test runner is used to execute test cases.
12. Explain parameterized tests.
Parameterized test feature in JUnit enables the developer to run a test multiple times using different values.
13. Give the difference between automated and manual testing.
| AUTOMATED TESTING | MANUAL TESTING | |
| Time Consumption | Less Time Consuming | More Time Consuming |
| Investment In Human Resources | Requires automation tools so no investment in human resources | Requires more investment in human resources since not dependent on tools |
| Reliability | More reliable | Less reliable |
| Programmable | Programming can be done to gather sophisticated information | No programming can be done. |
14. What are JUnit classes used for?
JUnit classes are used to write and test Unit testing.
15. List some Junit classes.
Some important JUnit classes are:
- Assert
- Testcase
- TestResult
- TestSuite
16. How do you compile a JUnit class?
JUnit is compiled in a similar fashion as that of other Java classes. The important thing to remember while compiling JUnit is that JUnit JAR files must be included in classpath.
17. Even after compiling a test successfully, why does the execution fail?
This happens when the test method is declared as “private”. JUnit requires all the methods to be declared “public”
18. How to test a “protected” method?
While testing a “protected” method, the class is defined in the same package as the target class.
19. How to test a “private” method?
The “private” method cannot be directly tested, so either the method is changed from “private” to “protected”, or manual testing is performed
20. Name some tool to integrate JUnit easily.
The tools with which JUnit is integrated easily are:
- Eclipse
- Maven
- Ant
21. What is JWebUnit?
JWebUnit is used for testing web applications by the developers. It wraps different frameworks like HtmlUnit and Selenium with a single easy and simple testing interface which allows the testing of the web applications to be more accurate.
22. List some important JUnit annotations
Annotations in JUnit give us information about which test will run before and after test methods and which method will run before or after all the test methods. Some important annotations are:
- Test
- Before Class
- Before
- After Class
- After
These top 22 JUnit interview questions will help you get a good recap of the topic and once you revise the concepts, you are ready to become a developer.
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