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NUnit Interview Questions and Answers

This article is focused on frequently asked NUnit Interview Questions that cover NUnit’s Core features, Attributes, installation, and many more. Let’s drive into the article and learn more about NUnit Test

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We all know that the testing phase plays an important role in every project cycle. So same, if you want to know how the application can be used in any software environment you need to test your application. So here in this article, we’re discussing NUnit Testing. 

Are you looking for NUnit Test Interview Questions and answers? Then you landed on the right page. NUnit test is a vital phase in software testing. So here, our team experts compiled the Top 20 NUnit Interview Questions and Answers for Freshers and Experienced candidates. These Best NUnit Test Interview Questions will help to clear your interview. 

In this blog, you will learn these topics

NUnit Interview Questions For Freshers

1. What is a NUnit Test?

Ans: NUnit is a unit-testing library that works with any.Net language. The current development release, version 2.2, is the fourth huge update of this xUnit considered a useful testing tool for Microsoft. NET, which was originally migrated from Junit. It's completely written in C# and has been totally rewritten to reap the benefits of many of the.NET language's features, such as custom attributes and other reflection-related features. NUnit adds xUNit support to all.NET languages. 

2. What are the advantages of the NUnit Test?

Ans: Following are some of the advantages of the NUnit Test:

  • NUnit is a framework for automating unit testing in all.Net languages.
  • Traditionally adapted from Junit, which is a Cross platform unit testing framework.
  • It has been extensively rebuilt to take advantage of many.NET language capabilities and is written entirely in C#.
  • NUnit adds xUNit support to all tests written in a.NET supported language, such as C#, VC, VB.NET, J#, and others.
  • NUnit is a free open-source testing framework for.NET projects.
  • Nunit supplies a class library with certain classes, attributes, and operations to aid in the creation of test scenarios.
  • NUnit is a user interface program that allows you to run test scripts and see the results.
  • NUnit does not generate its test scripts. To make unit testing easy and present the results as a success or failure, we must develop test scripts and use NUnit tools and classes.
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3. What are the core features of NUnit Test?

Ans:  Subsequent are the core features of NUnit test: 

  • You develop NUnit test scripts that are explicitly defined with custom Attributes to test an application.
  • Assertions are statements in your source code that demonstrate the application's correct operation.
  • NUnit allows you to have configurations for your test that are distinct from those used in development if your application keeps settings in Configuration Files.
  • NUnit supports tests classified as Multiple Assemblies, as well as designing and executing tests as NUnit Test Projects, in addition to running tests in a single assembly.
  • Visual Studio Support is provided for individuals running NUnit on a Pc Or laptop with Visual Studio deployed.

4. Explain about Assertions in NUnit test?

Ans: In Unit testing, any of the xUnit libraries rely heavily on assertions, and there is no exception for NUnit. As a static method of the Assert class, NUnit provides a large number of assertions.

The method call doesn't really return if an assertion fails, and an exception is reported. Any assertions that accompany the one that failed will not be run if the test has several assertions. As a result, it's usually preferable to limit yourself to one assertion for each test.

Every method can be called with or without a response, as well as with or without parameters. The message is generated using the specified text and parameters in the last case. There are two assertion models in NUnit Test: 

Classic Model: Before NUnit 2.4, each assertion was handled by various types of Assert class functions. This is referred to as the classic model. 

Constraint Model: A revolutionary constraint-based framework is being introduced with NUnit 2.4. This function passes a constraint class that determines the test to be conducted to a particular method of the Assert interface for all assertions.

Now, NUnit uses this constraint-based approach for all assertions implicitly. On top of this new model, the procedures of the conventional approach have been re-implemented.

Related Article: Unit Testing Interview Questions

5. Give detailed information about the Classic model?

Ans: The traditional Assert model has a separate method for expressing each individual assertion that it is capable of.

Here's an example of a simple assertion using the classic model:

AreEqualIgnoringCase("Hi", Name); 

The most prevalently used assertions are provided by the Assert class. For the sake of presentation, we categorize Assert methods as follows:

Identity Assert:  Assert.AreSame and Assert. AreNotSame determines whether the two arguments refer to the same objects.

Type Asserts: We can use these techniques to create assertions about the characteristics of an object.

Utility Methods: To allow  full control of the testing process, two utility methods, Fail() and Ignore(), are provided

Equality Asserts: These techniques determine whether the two methods are equivalent or not. Overloaded methods for prevalent data types so that languages that do not invariably box attributes can use them effectively.

Comparison Asserts: In this technique, it compares two objects to see if one is greater than the other. These techniques are supposed to be read in the "traditional" English-language or algebraic order, rather than the usual sequence of Asserts. As a result, Assert. Greater(x, y) claims that x exceeds y (x > y).

Greater(x, y) claims that x exceeds y (x > y).

Condition tests: Techniques that test a specific condition are designated after the condition they are testing and accept the value being tested as to their first parameter and, optionally, a message as their second parameter.

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6. Explain about Constraint Model?

Ans:  All assertions in the constraint-based Assert model are handled by a single method of the Assert class. The logic required to carry out each assertion is integrated in the constraint attribute passed as the technique's second parameter.

Here's a very simple constraint model assert:

Assert. that( MyStringName.Is.EqualTo("Hi");

The second argument in this assertion creates an EqualConstraint using one of NUnit's syntax assistants. The same claim could be created in this format:

Assert.That (myStringName, new EqualConstraint("Hi, World"));

All assertions in this framework are made using one of the Assert forms.

There are several overloads for the That() method.

In each case, the overloads that accept a bool component are exactly like Asser. IsTrue.

For overloads that take a constraint, the assertion must be an entity that implements the IConstraint functionality and can perform a test on an actual value while also creating appropriate messages. This functionality is covered in greater depth under Custom Constraints.

Equal Constraint: An EqualConstraint is used to determine whether a real value is equal to the average value provided in the constructor.

Is a Syntax HelperConstructorOperation.

EqualTo(object) EqualConstraint(null) determines whether or not two objects are equal.

SameAsConstraint:  It is used to determine whether the entity managed to pass as a real value has the same individuality as the entity delivered in its constructor.

Syntax:  HelperConstructorOperation.

SameAs(object) and SameAsConstraint(null) check whether two entity references refer to the same attribute.

Condition Constraint: Condition Constraints test a particular condition and are named after it. They ensure that the real value meets the circumstance.

Comparison constraints: It can determine whether one value is higher or less than the other. Arithmetic values, as well as many other things that integrate IComparable, are subject to comparative constraints.

Type Constraints: Type constraints operate Type-specific tests.

String Constraints: String constraints operate string-specific tests.

NUnit Interview Questions and Answers for Experienced

7. Explain about Attributes in NUnit test?

Ans: The traditional way of defining tests in NUnit was dependent on inheritance and naming constraints. NUnit has been using optimistic attributes for this purpose since version 2.0.

The developer can utilize inheritance in other ways because NUnit test components do not inherit from a platform class. Because there is no arbitrary naming requirement for tests, the names chosen can be fully focused on explaining the test's objective.

The NUnit.Framework domain contains all NUnit properties. The application must specify the platform assembly, nunit.framework.dll, and each source file containing tests must include a using-declaration for that domain. Following that, there are many types of attributes:

CategoryAttribute: When dealing with groupings of tests, the Classification attribute is equivalent to suites. Individual test scenarios or fixtures can be classified into one of several categories. This feature is enabled via the console runner's /include and /exclude parameters, as well as a dedicated "Categories" page in the gui. The user interface shows which sections are selected at any given time.

Description: The descriptive text is applied to a Test, TestFixture, or Component using the Description component. The text is visible in the Test Properties dialog and in the XML output file.

ExpectedExceptionAttribute: This is how you specify that a test will throw an exception when it is run. This variable has a variety of named and positional parameters, which we'll go over in various parts depending on what they do.

ExplicitAttribute: Unless a test or test fixture is expressly designated for running, the Explicit value causes it to be discarded. If the test or component is identified in the gui, its name is supplied on the prompt runner command-line interface as the component to run, or it is included via a Category filter, it will be run.

IgnoreAttribute: The ignore attribute tells the test or unit component not to run for a certain amount of time. The Ignore Attribute is applied to either a Test or a TestFixture. When the running software notices the attribute, it skips the test or tests. If a test is not run, the progress indicator will turn yellow, and the test will be indicated in the reports as not having been run.

8. What is meant by Configuration files in NUnit Test?

Ans: NUnit utilizes configuration files for both the test interpreter executable (NUnit-console.exe or nunitgui.exe) and the tests that are executed. Only NUnit-console.exe.config and NUnit-gui.exe.config settings should be in the nunit-console.exe.config and NUnit-gui.exe.config files, meanwhile your application and procedures should be in a distinct configuration file.

NUnit Configuration Files: The NUnit-gui config files' and NUnit console main function is to enable NUnit to perform with new iterations of the.NET framework. Versions 1.1 and 2.0 of the technology are used to create NUnit. Both configurations are available as separate packages, and either can be converted to work with various CLR versions.

The portion of each template is filled out by default, causing NUnit to operate with the version of.NET that was used to create it. The entries in this section govern the sequence in which various framework versions are considered.

Test Configuration Files: Specific naming regulations must be followed when using a configuration file to give parameters or govern the environment in which a test is conducted.

If just one assembly is loaded, the configuration file is given the assembly file's name plus the config attachment. The filesystem for nunit.tests.dll, for example, must be titled nunit.tests.dll.config and placed in the same folder as the dll.

If an NUnit project is imported into a solitary AppDomain, the template has the same name as the project file but with the attachment template. The application AllTests.NUnit, for example, would necessitate a template titled AllTests.config in the same folder as AllTests.nunit. When uploading Visual Studio files or solutions, the same principle is applicable.

9. Explain about Multiple Assemblies in NUnit test?

Ans: Both the console and GUI runners of NUnit now support loading test suites from different assemblies. This can be done on an individual scale or by exporting NUnit test packages as '.nunit' files. In either instance, a top-level suite containing the root suite for each assembler is created. Tests are carried out and results are presented in the same way as they are for a single assembly.

Adhoc Usage: Multiple assemblies can be executed with the console interpreter by simply entering their identities on the command-line interface. For an illustration of this, see NUnit-Console Command Line Arguments.

Multiple assemblies cannot be specified on the command line with the GUI runner. You may, however, import a single assembly and subsequently add other assemblies using the Project menu. You can also drag several assemblies to the tree view pane, which will substitute any assemblies that are currently loaded.

NUnit Test Projects: NUnit test projects make it easier to run tests across many assemblies. These are.nunit files that include data on the assemblies that will be loaded. An instance of a potential test project file is as follows:

<Settings activeconfiguration="DebugCong"/>
 <Config name1="DebugCong">
<assembly path1="LibraryCore\bin\Debug\Library.dll"/>
<assembly path1="LibraryUI\bin\Debug\LibraryUI.dll"/>

Loading and Running: The current directory has always been set to the folder comprising the solitary imported assembly, which has proven convenient for test writers. When any test from that assembly is run, NUnit helps to redefine the root directory to the location comprising that assembly for interoperability reasons.

Because certain assemblies rely on unregulated dlls in the same path, the existing directory is set to the assembly's directory when the assembly is imported. However, in circumstances when numerous assemblies connect to the same unregulated assembly, this may not be enough, and the client may need to include the unregulated dll directory to the path.

10. Explain about Visual Studio Support in NUnit Test?

Ans:  This release's support for Visual Studio is similar to a "poor man's unification." We built a number of features without requiring the use of an Addin or otherwise dealing with the Visual Studio extension framework.

Running from Visual Studio: Setting up a customized tool setting with the address to NUnit as the parameter is the most suitable technique to do this. Following are the some options that are compatible with both versions:

To access VS Project instead of the assembly, use $(ProjectDir)$(ProjectFileName):If we utilize this method, make sure our config file is renamed appropriately and saved in the similar folder like the VS file name.

For running the assembly directly, go to $(ProjectDir)bin/Debug/$(TargetName)$(TargetExt). Note that some of the addresses, including the settings, must be hard-coded.

If you want to analyze your tests, utilize the Visual Studio Debugging | Processes items on the menu to interface to the NUnit after it has been started, and then create thresholds in our test code as required before executing them.

Using Console Interface to Debug Applications: When the nunit-console code is written in the test environment in Visual Studio, it recognizes this and displays the results to the Visual Studio command window.

Opening Visual Studio Projects: File Open window describes the essential authorized Visual Studio process to build when Visual Studio compatibility is enabled: C#, J#, C++, and VB.Net. The variables and the output assembly locations are discovered after reading the project file.

Opening Visual Studio Solutions: Solution files can be opened if Visual Studio support is enabled. The tree will be loaded with all output assemblies from enclosed projects of the permitted classes. It will be feasible to load and execute tests directly using this way if all enclosed projects are situated in directories beneath the package.

11. Give detailed information about the Nunit Extensibility?

Ans: NUnit is built to be extensible in a variety of different ways.

Custom Asserts, which are developed by developers to define the tests that belong to their projects, are the most common enhancements to the NUnit framework - the portion of NUnit that is required by tests.

The use of NUnit Addins is required to extend the functionalities provided within NUnit. The Addin technique currently only accepts modifications to the NUnit core, which is the element of NUnit that produces and implements test suites. However, the API utilized allows the client-side of NUnit, including the GUI, to be extended in the future.

12. How to install NUnit?

Ans: Following are the few steps to install the NUnit in your system: 

Installation: The NUnit installation application saves all files in the C:Program FilesNUnit 2.4 folder by default. There are three directories in the project directory: bin, doc, and samples. The binary deployment of package is no longer included in the source code. If source is required, obtain the source folder.

Running NUnit: A variety of things are added to the Start menu by the installation program. According to the platforms of.NET or Mono accessible on your system at the time of deployment, there are a variety of alternatives that execute the NUnit GUI under different iterations of.NET or Mono.

Configuration: The configuration files nunit-console.exe.config and nunit.exe.config govern which iteration of the CLR is used when NUnit is executed from the command prompt or a workspace application. The part of the config file in question is commented out by default and should be left that way unless difficulties emerge.

Verification of the Installation: Run the NUnit gui and load and run NUnitTests.nunit from the local cache to ensure that the deployment went smoothly. All tests should be successful.

Timing Tests: Timing-tests.dll is an assembly that incorporates many lengthy procedures that are used to ensure that all remoting latency issues were resolved. The testing process takes six to twelve minutes to complete and give no evidence that they are functioning! This is essential since the purpose of these tests is to ensure the proper processing of non-communicative user requests.

Additional Tests: Additional tests are added to the original samples, as well as in independent assemblies that serve as data for the verification tests. These tests are designed to have failures or not run situations.

Manual Installation: If you're creating NUnit from source, the NAnt code is suggested for the final version because it gathers all of the essential files into a specific directory from which you can quickly transfer them. Follow these instructions to perform a manual installation:

-> Copy the subsequent files to the target folder:

  • Nunit.framework.extensions.dll 
  • nunit.framework.dll
  • nunit.core.dll

->Develop shortcuts.

->Copy the following files, together with any required dll config files, to the same directory as the others if you really want to run the nunit testing.

  • nonamespace-assembly.dll
  • mock-assembly.dll
  • notestfixtures-assembly.dll
  • nunit.core.tests.dll

13. Explain about NUnit test Framework?

Ans: NUnit is a unit-testing mechanism for.NET applications that isolate the existing applications into multiple modules. Each module is separately checked to ensure that the objective is achieved. The NUnit framework supports a variety of properties used in unit tests. Ignore methods, Test methods, expected exception, and  Test -Fixtures, all are defined.

14. How is NUnit used in unit testing?

Ans: A method with the Test parameter is a test method. Use the file and run dotnet test to create the tests and the object library, followed by running the tests. The NUnit test server is where you run your assertions because it has the program access point.

15. What languages does NUnit support?

Ans: NUnit is currently developed in C#, an object-oriented programming (OOP) language that integrates the capability of C++ with the ease of use of Visual Studio. NUnit is a member of the xUnit library of testing frameworks.

16. Is NUnit a GUI runner?

Ans: Nunit.exe is visual running software. It displays the tests in an interceptor web browser and gives a visual display of whether they passed or failed. It allows you to run specific tests or suites manually, and it reloads itself as you change and reload your code. A snapshot of NUnit executing the same mock-assembly.dll as in the nunit-console example is given below.

Tree Display: This version of NUnit incorporates symbols into the test tree, allowing users who are colour blind to detect the validation techniques. Completed tests are marked with a green checkbox. Ignored tests are indicated by a yellow circle with a question mark. Any tests that failed would be highlighted in red and marked with an X.

Progress Bar: The progress meter indicates how far the test has progressed. It is color-coded according to the "worst" outcome: red for failures, yellow for tests that were skipped, and green for accomplishment.

Results Tabs: The results of executing a test are displayed in the tabs down the bottom of the frame. For both surprising exceptions and assertion failures, the Exceptions and Failures tab provides the message box and stack trace. If the application was generated with debug data, the program for each stack position can be exposed in the tab.

Mini-Gui: An alternate "mini-gui" has been offered since the release of NUnit 2.4. It can be found under the View menu. The small gui window has been placed next to the Visual Studio IDE in the accompanying screenshot so that both components can be seen.

17. Explain about NUnit console runner?

Ans: Nunit-console.exe is a word-based runner that may be used to execute all of your tests without needing a green/red/yellow signal of accomplishment. It can be used to automate tests and integrate with other applications.

18. What is the pairwise attribute?

Ans: The PairwiseAttribute has been used on testing to tell NUnit that all potential sets of values should be used when generating test cases. Because more than two parameters (variables) are concerned, this is a well-known method for avoiding the sequential inflation of test cases. For instance: 

The following test would be run 12 (3x2x2) times by using the Combinatorial attribute. It is only executed numerous times with Pairwise to cover all possible pairs.

[Test, Pairwise]
public void MyTest1(
[Val("X", "Y", "Z")] string X,
[Val("*", "/")] string Y,
[Val("a", "b")] string Z)
    Console.WriteLine1("{0} {1} {2}", x,y,z);

19. Explain about Combinatorial Attribute?

Ans: On a test, the CombinatorialAttribute specifies that NUnit should produce test cases for all conceivable combinations of the particular data chunks provided for the test's parameters. The use of this attribute is discretionary because it is the default. For instance: 

[Test, Combinatorial]
public void MyTest1(
[Val(0, 1, 2)] int x,
[Values("X", "Y")] string s)

20. Explain about OneTimeSetup Attribute?

Ans: This parameter is used to identify methods that are executed only once before any of the tests in a configuration are run. It can occur on SetUpFixture or TestFixture procedures.

You can create many OneTimeSetUp functions in a fixture, and they can be static or instance methods. As mentioned below, additional OneTimeSetUp methods are normally only defined at various levels of an inheritance structure. None of the methods in the fixture is run if an OneTimeSetUp function fails or throws an exception, and a fault or error is detected.

For Example: 

namespace NUnit.Tests1
  using Sys;
  using NUnit.Framework1;
  public class SuccessTests1
    public void Init()
    { /* the data */ }
    public void Cleanup()
    { /* the data */ }
    public void Add()
    { /* the data */ }


We tried to cover all the topics and we hope the above NUnit interview questions and answers will help to crack your interview. If you experienced any interview before and you came across with different questions please comment in the below section we will get back to you ASAP with the best solution.

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Madhuri is a Senior Content Creator at MindMajix. She has written about a range of different topics on various technologies, which include, Splunk, Tensorflow, Selenium, and CEH. She spends most of her time researching on technology, and startups. Connect with her via LinkedIn and Twitter .

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