Frequently asking TestNG Interview Questions

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Question# 1: Can you tell me which unit test framework do you use?

Answer: TestNG

Question# 2: What is TestNG?

Answer: TestNG is a testing framework which is used to make testing activities simpler, effective, convenient and disciplined.

Question# 3: What does NG mean in TestNG?

Answer: NG stands for ‘Next Generation’. It is the next generation of framework after Junit.

Question# 4: What are the testing processes are testable with TestNG?

Answer: We use TestNG for the broad range of testing processes from Unit testing to Integration testing.

Question# 5: What are the importance of using TestNG in our automation project?

Answer: We use TestNG for the following benefits:

• We define different test activities within annotations
• It supports parallel execution of the test cases
• TestNG supports default threading in parallel execution
• We define dependencies of one test methods/groups over another
• TestNG effectively helps to define test groups
• It supports priority assignment to the Tests
• Parameterizations are easily implemented using @Parameters annotation in TestNG
• Data-driven testing is efficiently implemented using @DataProvider annotation in TestNG
• Different types of Assertion commands are available to validate the scenarios
• We can even run TestNG based Selenium projects from the command prompt
• It gives a detailed test report
• TestNG supports retry of failed test cases multiple times
• We can easily implement listeners through ITestListener
• TestNG separately creates an XML file for failed test scenarios

Question# 6: What are different annotations available in TestNG?

Answer: Click here to know details about annotations in TestNG.

Question# 7: How do we run tests created through TestNG?

Answer: We trigger tests through the testng.xml file.

Question# 8: What are the significances of the testng.xml file?

Answer: Followings are the significances of testng.xml file:

• All the tests are triggered by testng.xml file
• It supports inclusion and exclusion of the tests
• Parameters are passed from testng.xml file
• It supports the addition of dependency of groups
• Parallel execution and thread counts are defined in the testng.xml file
• XML creates child XML file for failed tests as testng-failed.xml

Question# 9: Can we run TestNG Selenium project from the command prompt?

Answer: Yes.

Question# 10: What are assertions in TestNG?

Answer: TestNG supports various Assert commands to validate the expected and actual conditions of the scenarios. Some of the Assert commands in TestNG are as follows:

• assertEquals(String actual, String expected)
• assertNotEquals(String actual, String expected)

Question# 11: How do we send parameters from a testng.xml file?

Answer: testng.xml support parameterization for @Parameters annotation so we send values from testng.xml by defining below statement:

<parameter name=”name of the parameter” value=”value of the parameter”>

Question# 12: Can we handle expected exceptions with TestNG?

Answer: Yes.

Question# 13: How do we handle expected exception with TestNG?

Answer: We use the following statement to handle expected exception with TestNG:

1	@Test(expectedExceptions=ArrayIndexOutOfBoundsException.class)

Question# 14: How do we set the execution priority of the tests?

Answer: We use priority keyword along with @Test annotation to set the priority of the test. Below statement sets the priority of the test:

@Test(priority=0)

public void test1(){

}

@Test(priority=1)

public void test2(){

}

Question# 15: What are different techniques to implement parameterization in the Selenium project with TestNG?

Answer: We achieve parameterization in Selenium with TestNG by following techniques:

• Parameterization through @Parameters annotation
• Parameterization through @DataProvider annotation

Question# 16: How do we combine tests with same group identifications?

Answer: We use groups keyword to combine tests of the same group. Here is the implementation:
@Test (groups = {“groupName1”,  “groupName2”})

Question# 17: How to include and exclude groups from testng.xml?

Answer:

<groups>

<run>

<exclude name=”group1”>

<include name=”group2”>

</include>

</exclude>

</run>

</groups>

Question# 18: How are tests run in parallel in TestNG?

Answer: We use “parallel” keyword to run tests in parallel.

Question# 19: How to starts different threads in parallel in TestNG?

Answer: We give integer value to the keyword “thread-count” in the testng.xml file to start multiple threads in parallel.

Question# 20: What are parallel attributes in TestNG?

Answer: Parallel keyword has following attributes to trigger tests in parallel:

• tests
• classes
• methods
• instances
• true
• false

Question# 21: How to skip tests at runtime with TestNG?

Answer: We throw SkipExceotion(String message) to skip tests at runtime.

Question# 22: Can we ignore some tests with TestNG?

Answer: Yes.

Question# 23: How to ignore tests with TestNG?

Answer: We use the following statement with the @Test annotation to ignore tests with TestNG.
@Test(enabled=false)

Question# 24: How to define dependencies with TestNG?

Answer: We use the dependsOnMethods keyword to define dependencies with TestNG.

Question# 25: How to design a data-driven framework using TestNG?

Answer: We use @DataProvider annotation to design data-driven framework in Selenium with TestNG.

Click on below link to know more.

Question# 26: What is the return type of method within @DataProvider annotation?

Answer: Method implemented with @DataProvider annotation has 2-D Object as its return type.

Question# 27: How to perform advanced logging in Selenium with TestNG?

Answer: We use Test listeners to implement advanced logging with TestNG.

Question# 28: What are TestNG Listeners?

Answer: TestNG listeners are used for intelligent and advanced reporting and logging in the Selenium project. We implement TestNG listeners by following ways:

• TestNG listener implementation by- @Listener annotation
• TestNG listener implementation through the testng.xml file

Question# 29: What is the difference between listener implementation through @Listener annotation and through the testng.xml file?

Answer: TestNG listener implementation through @Listener annotation is restricted to a particular class only, whereas, listener implementation through the testng.xml file is applicable to the entire test suite.

Question# 30: How to implement TestNG listener through the testng.xml file?

Answer: We add following statement in testng.xml file to implement TestNG listener.

<listeners>

<listener class-name=”Class_Name”/>

</listeners>

Question# 31: What are the listeners’ name for logging and reporting in TestNG?

Answer: We implement ITestListener for effective logging and IReporter listeners for custom reporting in TestNG.

Here is the tutorials link for their implementation:

• How to create a custom TestNG report using IReporter?
• How to implement ITestListener in Selenium?

Question# 32: What is the interface name to implement test retry with TestNG?

Answer: We implement IRetryAnalyzer and IAnnotationTransformer interfaces to implement retry of failed tests with TestNG.

• How to retry failed tests with TestNG?

Question# 33: How to define a regular expression in the testng.xml file to search tests which contain keyword “regression”?

Answer:

<methods>

                <include name=”.*regression.*”/>

</methods>

Question# 34: What is the time unit to define in test suites?

Answer: milliseconds.

Question# 35: How to run particular test methods multiple times?

Answer: we use the following statement to invoke particular tests for a certain number of times.

@Test(invocationCount = 20)

public void myTest(){

}

Question# 36: How to run a test method from multiple different threads?

Answer: Following code specifies that myTest() method will be invoked from 5 different threads.

@Test (threadPoolSize = 5, invocationCount = 20)

public void myTest(){

}

Question# 37: How to give timeouts to different threads with TestNG?

Answer: We use ‘timeOut’ keyword to add the time delay. Here is the statement:

@Test (threadPoolSize = 5, invocationCount = 20, timeOut = 20000)

public void myTest(){

}

Question# 38: What is the use of @Factory annotation in TestNG?

Answer: @Factory annotation helps to run different classes from a sing class. It is also used to set the value of the parameterized constructor with the help of @DataProvider annotation.

Question# 39: What is the return type of method written within @Factory annotation?

Answer: The return type of the method written within @Factory annotation is 1D Object array.

Question# 40: What is the command to run TestNG using command prompt?

Answer:

set classpath=pathOfBinFolder/bin; pathOfLibFolder/lib/*;

java org.testng.TestNG pathOftestng.xml/testng.xml

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Here are some of the miscellaneous TestNG interview questions which are generally not asked in an interview, but you should have knowledge of it.

Question# 41: Which version of TestNG have you used in your previous project?

Question# 41: How did you install TestNG in your IDE?

Question# 42: Which IDE did you use for TestNG?

Question# 43: Have you extended your existing testng.xml file with another testng.xml file?

Question# 44: When did TestNG come in picture?

Question# 45: Who developed TestNG?

Question# 46: How is TestNG better than Junit?

Question# 47: What is the folder name generated after the first test run through the testng.xml file?

Question# 48: What is emailable-report in TestNG?

Question# 49: Can we pass a large set of parameters through @Parameters annotation?

Question# 50: How to perform inheritance in the testng.xml file?

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