Comparing .NET Testing Frameworks.

xunit/xunit : Community-focused unit testing tool

nunit/nunit : NUnit Framework

microsoft/testfx : MSTest framework and adapter

Target audience: A developer switching frameworks :)

Test Suites

Typically test classes and/or methods are decorated with Attributes.

xUnit IClassFixture

Setup in xUnit doesn’t work with Attributes!
xUnit injects the same XUnitTestsFixture to the constructor before running each [Fact].

public class XUnitTestsFixture : IDisposable
{
    public XUnitTestsFixture() { /* BeforeAllTests */ }
    public void Dispose() { /* AfterAllTests */ }
}

public class XUnitTestsWithSetUp : IClassFixture<XUnitTestsFixture>
{
    private readonly XUnitTestsFixture _fixture;

    public XUnitTestsWithSetUp(XUnitTestsFixture fixture)
    {
        _fixture = fixture;
    }

    [Fact]
    public void Test1() { }
}

Assembly setup

xUnit

As per the IClassFixture<T> example above, the XUnitTestsFixture will be injected in all test classes in the assembly.

[assembly: AssemblyFixture(typeof(XUnitTestsFixture))]

NUnit

[SetUpFixture]
public class Config
{
    [OneTimeSetUp]
    public void SetUp() { }

    [OneTimeTearDown]
    public void TearDown() { }
}

MSTest

[TestClass]
public class MyTestClass
{
    [AssemblyInitialize]
    public static void AssemblyInitialize(TestContext testContext)
    {
        // Or return Task!
    }

    [AssemblyCleanup]
    public static void AssemblyCleanup()
    {
        // Or return Task!
    }
}

Assertions

bool? actual = true;

// NUnit
Assert.That(actual, Is.EqualTo(true));

// xUnit
Assert.Equal(true, actual);

// MSTest
Assert.AreEqual(true, actual);

Basic

Strings

Exceptions

Action sut = () => throw new Exception("cause");
Func<Task> asyncSut = () => Task.CompletedTask;

// NUnit
var ex = Assert.Throws<Exception>(() => sut(), "failure message");
Assert.That(ex.Message, Is.EqualTo("cause"));

Assert.DoesNotThrowAsync(() => asyncSut());


// xUnit
var ex = Assert.Throws<Exception>(sut);
Assert.Equal("cause", ex.Message);

Assert.ThrowsAsync<Exception>(() => asyncSut());


// MSTest
// via Attribute
[TestMethod]
[ExpectedException(typeof(Exception))]
public void Exceptions() {}

// Via code
Assert.ThrowsExceptionAsync<Exception>(asyncSut);

Collections

xUnit Assert.Collection

Specific assertions per element in the collection.

Assert.Collection(
  collection,
  el1 => Assert.Null(el1),
  el2 => Assert.False(el2),
  ...
);

NUnit Dictionary Assertions

var dict = new Dictionary<int, int>
{
  { 1, 4 },
  { 2, 5 }
};

Assert.That(dict, Does.ContainKey(1).WithValue(4));

Assert.That(dict, Contains.Value(4));
Assert.That(dict, Does.ContainValue(5));
Assert.That(dict, Does.Not.ContainValue(3));

Numbers

// xUnit
// Only InRange
Assert.InRange(actual, 0, 100);

// NUnit
Assert.That(actual, Is.InRange(0, 100));
Assert.That(actual, Is.AtMost(0));
// Also: AtLeast, Zero, LessThanOrEqualTo, Negative/Positive
// Greater/LessThan uses IComparable

// MSTest: N/A

NUnit Only

Dates

Assert.That(later, Is.EqualTo(now).Within(TimeSpan.FromHours(3.0)));
Assert.That(later, Is.EqualTo(now).Within(3).Hours);

Directories

Also: Is.SamePath(OrUnder)

Assert.That("/folder1/./junk/../folder2", Is.SubPathOf("/folder1/"));
Assert.That(new DirectoryInfo("c:\\temp"), Does.Exist);
Assert.That(new DirectoryInfo("c:\\temp"), Is.Not.Empty);

And/Or

Assert.That(3, Is.LessThan(5).Or.GreaterThan(10));