NUnit vs. xUnit vs. MSTest

What is NUnit ?

NUnit is a free, open-source unit testing framework for .NET languages, inspired by JUnit. It allows you to test individual parts of your application separately to ensure they work correctly. NUnit provides custom attributes (like [TestFixture], [Test], and [SetUp]) to define and organize tests. The Assert class helps verify that the code behaves as expected by checking conditions, and if a test fails, it generates an error. NUnit is widely used and supports various .NET platforms.

Sample NUnit Test

using NUnit.Framework;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Support.UI;
namespace WebDriver_CSharp_Example
{
    [TestFixture]
    public class Chrome_Sample_test
    {
        private IWebDriver driver;
        public string homeURL;
        [Test(Description = "Check Homepage for Login Link")]
        publicvoidLogin_is_on_home_page()
        {
            homeURL = "https://...";
            driver.Navigate().GoToUrl(homeURL);
            WebDriverWait wait = new WebDriverWait(driver, System.TimeSpan.FromSeconds(15));
            wait.Until(driver => driver.FindElement(By.XPath("//a[@href='/beta/login']")));
            IWebElement element = driver.FindElement(By.XPath("//a[@href='/beta/login']"));
            Assert.AreEqual("Sign In", element.GetAttribute("text"));
        }
        [TearDown]
        publicvoidTearDownTest()
        {
            driver.Close();
        }
        [SetUp]
        publicvoidSetupTest()
        {
            homeURL = "http://...";
            driver = new ChromeDriver();
        }
    }
}

What is xUnit ?

xUnit.net is a free, open-source unit testing tool for .NET, created by the developers behind NUnit. It's designed to be community-focused and works well with tools like Xamarin, ReSharper, and TestDriven.NET. The "x" in xUnit indicates that it’s part of a family of unit testing frameworks for different programming languages (like JUnit for Java and NUnit for .NET).

xUnit allows you to customize your tests with various attributes and extends the functionality of the Assert class with methods like Contains, Equal, and InRange. It supports two main types of tests:

• [Fact]: A standard unit test that always runs the same way.
• [Theory]: A test that runs multiple times with different input data.

By default, xUnit runs tests in parallel across different classes, speeding up the testing process without needing extra configuration.

Sample xUnit Test

public class MathUnitxTest
{
    [Fact]
    public void Task_TestAddition()
    {
        var numA = 12,
            numB = 4,
            result = 16;
        var calculatedSum = MathOperation.Add(numA, numB);
        Assert.Equal(expectedValue, calculatedSum, 1);
    }
    [Fact]
    public void Task_TestMultiplication()
    {
        var numA = 5,
            numB = 4,
            result = 20;
        var calculatedOutput = MathOperation.Multiply(num1, num2);
        Assert.Equal(result, calculatedOutput, 2);
    }
}

What Is MSTest ?

MSTest is Microsoft's unit testing framework, built into Visual Studio, allowing developers to write and run tests directly within the IDE. There's also an open-source version called MSTest V2, available on NuGet, making it accessible for more projects. MSTest provides a variety of attributes to organize and execute tests at both the method and class levels, without needing additional tools.

Sample MSTest Test

namespace Messages.Tests;
using Microsoft.VisualStudio.TestTools.UnitTesting;


[TestClass]
public class ArithmeticMsTest
{
    [DataTestMethod]
    [DataRow(1, 2, 3)]
    [DataRow(2, 2, 4)]
    [DataRow(-1, 4, 3)]
    public void Task_TestAddition(int x, int y, int expected)
    {
        int sum = Basic.add(x, y);
        Assert.AreEqual(sum, expected);
    }
    [DataTestMethod]
    [DataRow(1, 2, -1)]
    [DataRow(2, 2, 0)]
    [DataRow(3, 2, 1)]
    public void Task_TestSubtraction(int x, int y, int expected)
    {
        int res = Basic.sub(x, y);
        Assert.AreEqual(res, expected);
    }
}