gen-snapshot-test

name	gen-snapshot-test
description	Add an xUnit snapshot-style test for ChildStateGenerator or ControllersGroupGenerator output. Use when adding a new emit branch, fixing generated code, or verifying that an attribute combination produces the expected partial class. Tests live in Aspid.Core.HSM.Generators.Tests/ and use Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit (already referenced).

gen-snapshot-test

Generate a focused test that drives one of the incremental generators with a sample input class and asserts on the produced source text.

Where the test goes

Aspid.Core.HSM.Generators/Aspid.Core.HSM.Generators/Aspid.Core.HSM.Generators.Tests/ — keep state-machine runtime tests under StateMachineTests/ and put generator tests under a new GeneratorTests/ subfolder.

Pattern

Use CSharpGeneratorTest<TGenerator, XUnitVerifier> (from Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit). Required references for the test compilation must include the runtime types the generator looks up via HsmClasses/HsmNamespaces — IState, IChildState, IController, ParentStateAttribute, ControllerGroupAttribute, ReverseExecuteAttribute. The test csproj already links those via <Compile Include="..\..\..\Aspid.Core.HSM\Assets\..." />, so they are available as in-test source rather than a packaged reference.

Skeleton

using Microsoft.CodeAnalysis.CSharp.Testing;
using Microsoft.CodeAnalysis.Testing.Verifiers;
using Xunit;
using Aspid.Core.HSM.Generators.ChildState;

public class ChildStateGeneratorTests
{
    [Fact]
    public async Task ParentState_attribute_emits_IChildState_implementation()
    {
        const string input = """
            using Aspid.Core.HSM;
            namespace Sample;

            public partial class Root : IState { }

            [ParentState(typeof(Root))]
            public partial class Leaf : IState { }
            """;

        const string expected = /* paste generated source here */;

        var test = new CSharpSourceGeneratorTest<ChildStateGenerator, XUnitVerifier>
        {
            TestState =
            {
                Sources = { input },
                GeneratedSources =
                {
                    (typeof(ChildStateGenerator), "Leaf.g.cs", expected),
                },
            },
        };

        await test.RunAsync();
    }
}

Tips

• The generator skips classes that are not partial or that are static. Add a negative test for each.
• [ParentState(null)] is the root-state path; cover it separately from the typeof(Parent) branch.
• For ControllersGroupGenerator, exercise [ReverseExecuteAttribute] and [AsyncAttribute] combinations on group methods — those drive different emit branches in ControllerGroupBody.
• Equality of incremental pipeline records (ChildStateData, ControllerGroupData) matters for caching; if you add fields, add a test that two equal inputs produce a single Transform invocation.