Difference Between Microsoft Unit Test and xUnit

Choosing a testing framework for the .NET core can be confusing and challenging. The test framework should be designed and selected in a manner that can suit the requirements and needs of a particular project.

The testing frameworks are available in multiple and diverse options. The two most common and popular frameworks and tools for unit testing in C# are Microsoft Unit Test and xUnit.

Microsoft Unit Test vs xUnit

The main difference between Microsoft Unit Test and the xUnit is that Microsoft Unit Test provides lower isolation of tests while xUnit provides higher isolation of tests. The Microsoft Unit Test is a less community-focused and less sophisticated framework while xUnit is a more community-focused and more sophisticated framework.

Microsoft Unit Test vs

MSTest stands for Microsoft Unit Test. The other name for the framework in Visual Studio Unit Testing Framework. The shipping of the framework is done along with Visual Studio.

The framework can be installed from NuGet GUI or even through ‘NuGet Package manager console commands’.

On the other hand, xUnit is based on the framework of .NET. The ‘x’ of xUnit stands for the type of programming language used in the framework. The xUnit framework can be installed from GitHub.

The expansion and extension of xUnit are higher than most other frameworks.

Comparison Table Between Microsoft Unit Test and xUnit

Parameters of Comparison Microsoft Unit Test xUnit
Initialization and De-initialization [TestInitialize] and [TestCleanup] to initialize and de-initialize respectively Can be initialized by using the constructor of the test class and can be de-initialized by using an Idisposable interface
Parallel Test ExecutionParallel execution is offered at class level as well as method level Parallel execution is offered by execution of ‘n’ number of threads or allowing the test classes into a single test collection
Isolation of tests Provides lower isolation Provides better isolation
ExtensibilityComparatively less extensible More extensible as it uses attributes like [Fact] and [Theory]
Mechanism for assertion Uses [ExpectedException] Uses Assert.Throws

What is Microsoft Unit test?

Microsoft Unit Test ( MSTest) also known as Visual Studio Unit Testing Framework, is the default test framework. The tool is shipped with Visual Studio. Initially, the tool was used as a common-line to execute tests.

The framework caters to the required tools to validate, check and verify the provided source code. The execution time is less in MSTest because tests can execute and run parallel.

The recognition of the test by the framework is through several annotations and attributes, with the help of various test codes. Some common attributes are [TestInitialize], [TestCleanup], [TestMethod] and others.

The tool has a pre-bundle of Visual Studio. The successful run of the Microsoft Unit Test solely depends on the installation of the MSTest Adapter.

The installation process of Microsoft Unit Test is through NuGet GUI or even through ‘NuGet Package manager console commands’.

The installation of the packages is by the use of the ‘Install-Package’ command along with the argument. The test behavior of the users can be defined in Microsoft Unit Test by catering to several input arguments.

Packages like MSTest.TestAdapter, Microsoft.NET.Test.Sdk and MSTest.TestFramework is essential for the working of the framework. The initial MSTest V1 was not open-source, but later V2 was launched as an open-source.

Microsoft Unit Test is cross-platform. It allows the implementation of various test targeting on platforms like Windows, Linux, or Mac. It also has provision for extensibility for custom attributes and asserts.

What is xUnit?

xUnit is a testing tool that is used for .NET Framework. It is a free and open-source unit. The license of xUnit is under Apache License 2.0. The availability of the source code is on GitHub.

The work of xUnit.net is with CodeRush, Xamarin, TestDriven.NET, and ReSharper. The authors are James Newkirk and Brad Wilson.

The developers of xUnit.net are Outercurve Foundation, Microsoft, and .NET foundation. The tool was released on October 29, 2018, in version 2.4.1. The tool is exclusively written in the C# language.

The operating systems that are compatible with xUnit are macOS, Windows, and Linux. The platforms that support the unit testing tool are Mono,.NET Framework, and.NET Core. The tool is community-focused.

xUnit was written by the same individual who is the inventor of NUnit v2. The introduction of the tool was to help programmers write better and clearer tests.

The testing framework was also brought close in line with the .NET platform, after the introduction of the tool. xUnit built an architecture for programmers especially for the development of Test-Driven.

The extension of supporting another testing like automated acceptance tests is also included in the xUnit tool.

xUnit can be easily expanded. The tool is downloaded from the NuGet gallery. The tool allows and unique and different style of testing.

The tool can be initialized by using the constructor of the test class and can be de-initialized by using an Idisposable interface. xUnit is considered extensible and a robust testing tool.

Main Differences Between Microsoft Unit Test and xUnit

  1. The Microsoft Unit Test is a less community-focused and less sophisticated framework while xUnit is a more community-focused and more sophisticated framework.
  2. The attribute to mark a test method or individual test is [TestMethod] in Microsoft Unit Test while [Fact] in xUnit.
  3. The attribute to indicate a group of unit tests of a class is [TestClass] in the Microsoft Unit test while no such attribute is present in the xUnit framework.
  4. Microsoft Unit Test does not contain fixture setup and teardown attributes while ICollectionFixture<T> is used in xUnit per collection.
  5. Microsoft Unit Test was not launched as an open-source testing framework initially while xUnit was launched as open-source testing.


Unit testing plays a crucial role in any component of the software. It helps the developers to identify and correct their code. It minimizes the scope of bugs and threats in the code.

And some developers even prefer to write the unit test before the code. This process is known as test-driven development or TDD.

The two most common unit tests of C# language are Microsoft Unit Test and xUnit. Both the testing tools have different features and attributes. Both perform in different ways.

Developers and programmers need to evaluate all the parameters before including the unit test in the code.


  1. https://ieeexplore.ieee.org/abstract/document/7155685/
  2. https://link.springer.com/chapter/10.1007/978-3-642-15585-7_11
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