dotnet-test-frameworks

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Reference data for .NET test framework detection patterns, assertion APIs, skip annotations, setup/teardown methods, and common test smell indicators across MSTest, xUnit, NUnit, and TUnit. DO NOT USE directly — loaded by test analysis skills (test-anti-patterns, exp-test-smell-detection, exp-assertion-quality, exp-test-maintainability, exp-test-tagging) when they need framework-specific lookup tables.

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.NET Test Framework Reference

Language-specific detection patterns for .NET test frameworks (MSTest, xUnit, NUnit, TUnit).

Test File Identification

Framework	Test class markers	Test method markers
MSTest	`[TestClass]`	`[TestMethod]` , `[DataTestMethod]`
xUnit	(none — convention-based)	`[Fact]` , `[Theory]`
NUnit	`[TestFixture]`	`[Test]` , `[TestCase]` , `[TestCaseSource]`
TUnit	`[ClassDataSource]`	`[Test]`

Assertion APIs by Framework

Category	MSTest	xUnit	NUnit
Equality	`Assert.AreEqual`	`Assert.Equal`	`Assert.That(x, Is.EqualTo(y))`
Boolean	`Assert.IsTrue` / `Assert.IsFalse`	`Assert.True` / `Assert.False`	`Assert.That(x, Is.True)`
Null	`Assert.IsNull` / `Assert.IsNotNull`	`Assert.Null` / `Assert.NotNull`	`Assert.That(x, Is.Null)`
Exception	`Assert.Throws<T>()` / `Assert.ThrowsExactly<T>()`	`Assert.Throws<T>()`	`Assert.That(() => ..., Throws.TypeOf<T>())`
Collection	`CollectionAssert.Contains`	`Assert.Contains`	`Assert.That(col, Has.Member(x))`
String	`StringAssert.Contains`	`Assert.Contains(str, sub)`	`Assert.That(str, Does.Contain(sub))`
Type	`Assert.IsInstanceOfType`	`Assert.IsAssignableFrom`	`Assert.That(x, Is.InstanceOf<T>())`
Inconclusive	`Assert.Inconclusive()`	skip via `[Fact(Skip)]`	`Assert.Inconclusive()`
Fail	`Assert.Fail()`	`Assert.Fail()` (.NET 10+)	`Assert.Fail()`

Third-party assertion libraries:

Should*

(Shouldly),

.Should()

(FluentAssertions / AwesomeAssertions),

Verify()

(Verify).

Sleep/Delay Patterns

Pattern	Example
Thread sleep	`Thread.Sleep(2000)`
Task delay	`await Task.Delay(1000)`
SpinWait	`SpinWait.SpinUntil(() => condition, timeout)`

Skip/Ignore Annotations

Framework	Annotation	With reason
MSTest	`[Ignore]`	`[Ignore("reason")]`
xUnit	`[Fact(Skip = "reason")]`	(reason is required)
NUnit	`[Ignore("reason")]`	(reason is required)
TUnit	`[Skip("reason")]`	(reason is required)
Conditional	`#if false` / `#if NEVER`	(no reason possible)

Exception Handling — Idiomatic Alternatives

When a test uses

try

/

catch

to verify exceptions, suggest the framework-native alternative:

MSTest:

csharp

// Instead of try/catch (matches exact type):
var ex = Assert.ThrowsExactly<InvalidOperationException>(
    () => processor.ProcessOrder(emptyOrder));
Assert.AreEqual("Order must contain at least one item", ex.Message);

// Or (also matches derived types):
var ex = Assert.Throws<InvalidOperationException>(
    () => processor.ProcessOrder(emptyOrder));
Assert.AreEqual("Order must contain at least one item", ex.Message);

xUnit:

csharp

var ex = Assert.Throws<InvalidOperationException>(
    () => processor.ProcessOrder(emptyOrder));
Assert.Equal("Order must contain at least one item", ex.Message);

NUnit:

csharp

var ex = Assert.Throws<InvalidOperationException>(
    () => processor.ProcessOrder(emptyOrder));
Assert.That(ex.Message, Is.EqualTo("Order must contain at least one item"));

Mystery Guest — Common .NET Patterns

Smell indicator	What to look for
File system	`File.ReadAllText` , `File.Exists` , `File.WriteAllBytes` , `Directory.GetFiles` , `Path.Combine` with hard-coded paths
Database	`SqlConnection` , `DbContext` (without in-memory provider), `SqlCommand`
Network	`HttpClient` without `HttpMessageHandler` override, `WebRequest` , `TcpClient`
Environment	`Environment.GetEnvironmentVariable` , `Environment.CurrentDirectory`
Acceptable	`MemoryStream` , `StringReader` , `InMemory` database providers, custom `DelegatingHandler`

Integration Test Markers

Recognize these as integration tests (adjust smell severity accordingly):

Class name contains
```
Integration
```
,
```
E2E
```
,
```
EndToEnd
```
, or
```
Acceptance
```
```
[TestCategory("Integration")]
```
(MSTest)
```
[Trait("Category", "Integration")]
```
(xUnit)
```
[Category("Integration")]
```
(NUnit)
Project name ending in
```
.IntegrationTests
```
or
```
.E2ETests
```

Setup/Teardown Methods

Framework	Setup	Teardown
MSTest	`[TestInitialize]` or constructor	`[TestCleanup]` or `IDisposable.Dispose` / `IAsyncDisposable.DisposeAsync`
xUnit	constructor	`IDisposable.Dispose` / `IAsyncDisposable.DisposeAsync`
NUnit	`[SetUp]`	`[TearDown]`
MSTest (class)	`[ClassInitialize]`	`[ClassCleanup]`
NUnit (class)	`[OneTimeSetUp]`	`[OneTimeTearDown]`
xUnit (class)	`IClassFixture<T>`	fixture's `Dispose`

dotnet-test-frameworks

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SKILL.md Content

.NET Test Framework Reference

Test File Identification

Assertion APIs by Framework

Sleep/Delay Patterns

Skip/Ignore Annotations

Exception Handling — Idiomatic Alternatives

Mystery Guest — Common .NET Patterns

Integration Test Markers

Setup/Teardown Methods