Test frameworks (TUnit, xUnit, NUnit, MSTest)

Nullean.Entities.CsCheck depends on no test framework. An auto-test throws when an axis fails, which every framework reports as a failed test, so RunAsync() works anywhere. To get one test per axis, so that a broken axis fails only its own test and the test explorer shows which law broke, hand the cases to your framework's data source:

AutoTest<T> and EventAutoTest<TSut, TEvent> both have AsDataSource(), CaseNames and Case(name). The cases include the deeper techniques you add (Exhaustive, Commutes(Confirm, Cancel), ...), named the way they are displayed.

TUnit takes the AxisCase itself. xUnit, NUnit and MSTest get the case's name instead, a plain string, and the test looks the case up again with Case(name). xUnit serializes theory data at discovery, and an AxisCase holds a delegate, which it cannot serialize. xUnit v3 then lists the whole theory as one test: it still runs every axis, but the test explorer shows a single entry, and you cannot run or re-run one axis by itself. A string serializes in every framework, so each lists one test per axis. NUnit 5 and MSTest 4 would also list AxisCase rows one per axis (they display ToString(), the axis name), but strings work the same way in all three.

Build the auto-test in a static method (Auto() below), not a field you mutate: the data source and the test each call it, so both see the same cases.

public static IEnumerable<Func<AxisCase>> Axes() => Auto().AsDataSource();

[Test]
[MethodDataSource(nameof(Axes))]
public Task EveryDeclaredAxisHolds(AxisCase axis) => axis.RunAsync();

The complete file is tests/Nullean.Entities.Quickstart.Tests/QuickstartTests.cs, shown in Getting started.

using Nullean.Entities.CsCheck;
using Nullean.Entities.Quickstart;
using Xunit;

namespace Nullean.Entities.TestFrameworks.Xunit;

// The one-liner docs/integration/test-frameworks.md shows: one theory row per axis the rules declare.
public class XunitAxesTests
{
	public static AutoTest<Order> Auto() => AutoTest.For(OrderConstraints.Instance, OrderAxes.Orders);

	public static TheoryData<string> Axes() => [.. Auto().CaseNames];

	[Theory]
	[MemberData(nameof(Axes))]
	public Task EveryDeclaredAxisHolds(string axis) => Auto().Case(axis).RunAsync();
}

TheoryData<string> keeps the xUnit analyzers quiet: an IEnumerable<object[]> member works too, but raises xUnit1042. Each test is displayed as EveryDeclaredAxisHolds(axis: "Monotonicity").

xUnit v2 has TheoryData<T> and serializes strings the same way, so the same lines apply. This repository tests xUnit v3 only.

using Nullean.Entities.CsCheck;
using Nullean.Entities.Quickstart;
using NUnit.Framework;

namespace Nullean.Entities.TestFrameworks.NUnit;

// The one-liner docs/integration/test-frameworks.md shows: one test case per axis the rules declare.
public class NUnitAxesTests
{
	public static AutoTest<Order> Auto() => AutoTest.For(OrderConstraints.Instance, OrderAxes.Orders);

	public static IEnumerable<string> Axes() => Auto().CaseNames;

	[TestCaseSource(nameof(Axes))]
	public Task EveryDeclaredAxisHolds(string axis) => Auto().Case(axis).RunAsync();
}

Each test is displayed as EveryDeclaredAxisHolds("Monotonicity").

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Nullean.Entities.CsCheck;
using Nullean.Entities.Quickstart;

namespace Nullean.Entities.TestFrameworks.MSTest;

// The one-liner docs/integration/test-frameworks.md shows: one data row per axis the rules declare.
[TestClass]
public class MSTestAxesTests
{
	public static AutoTest<Order> Auto() => AutoTest.For(OrderConstraints.Instance, OrderAxes.Orders);

	public static IEnumerable<string> Axes() => Auto().CaseNames;

	[TestMethod]
	[DynamicData(nameof(Axes))]
	public Task EveryDeclaredAxisHolds(string axis) => Auto().Case(axis).RunAsync();
}

Each test is displayed as EveryDeclaredAxisHolds ("Monotonicity").

Every snippet above is a file in a test project of its own that ./build.sh test runs with dotnet run (each is a Microsoft.Testing.Platform executable: xUnit v3 with UseMicrosoftTestingPlatformRunner, NUnit with EnableNUnitRunner, MSTest with EnableMSTestRunner). Each project also runs itself again as a child process (tests/Shared/TestFrameworks/FrameworkChecks.cs) and checks two things:

• --list-tests lists exactly one test per axis, one for each name in CaseNames.
• With an operation added that resets the order's version, the run reports one failed test, Monotonicity, and every other axis passed.