Asynkron.JsEngine: Command for Claude Code

Generate layered tests that verify each pipeline stage before full end-to-end runs.

For full methodology, see agents/how-to-layered-tests.md.

Pipeline Layers

Source -> Lexer -> Parser -> AST -> Analyzers -> Evaluator -> Result
   L0       L1       L2      L3       L4           L5

When to Use

• Bug manifests at runtime but stage is unclear
• Need to inspect AST/metadata before evaluation
• Validate scope/slot metadata, CPS, loop normalization
• Debug closure capture, environment chains, or slot lookups

Instructions

Given $ARGUMENTS (test name and JS code), create a test class with tests for each layer:

1. L2 Parser - Assert AST structure is correct
2. L3 Analyzers - Assert metadata (SlotMap, ScopeId, PerIterationBindings)
3. L4 Plans - Assert plan contents (e.g., LoopPlan, ExecutionPlan)
4. L5 Runtime - Enable debug logging and assert internal operations
5. L6 Result - Full evaluation assertion

Template

public class [TestName]LayeredTests
{
    private readonly ITestOutputHelper _output;
    public [TestName]LayeredTests(ITestOutputHelper output) => _output = output;

    private const string Source = @"/* javascript code */";

    [Fact]
    public void L2_Parser_AstStructure()
    {
        var pipeline = AstTestHelpers.ParseAndAnalyze(Source);
        var node = AstTestHelpers.FindFirst<ForStatement>(pipeline.Analyzed);
        Assert.NotNull(node);
        _output.WriteLine($"Found: {node.GetType().Name}");
    }

    [Fact]
    public void L3_Analyzers_SlotMetadata()
    {
        var pipeline = AstTestHelpers.ParseAndAnalyze(Source);
        var func = AstTestHelpers.FindFirst<FunctionExpression>(pipeline.Analyzed);
        Assert.NotNull(func?.SlotMap);
        Assert.True(func.SlotMap.ContainsKey(Symbol.Create("i")));
    }

    [Fact]
    public void L4_Plans_LoopPlan()
    {
        var pipeline = AstTestHelpers.ParseAndAnalyze(Source);
        var node = AstTestHelpers.FindFirst<ForStatement>(pipeline.Analyzed);
        var plan = ((IAstCacheable<LoopPlan>)node).GetOrCreateCache();
        var bindingNames = plan.PerIterationBindings.Select(b => b.Name).ToArray();
        Assert.Contains("i", bindingNames);
    }

    [Fact(Timeout = 10000)]
    public async Task L5_Result_Evaluation()
    {
        await using var engine = new JsEngine();
        var result = await engine.Evaluate(Source);
        Assert.Equal("expected", result?.ToString());
    }
}