testing

name	testing
description	Write, run, or improve xUnit tests for RegiLattice. Use when adding tests for a new feature, increasing coverage, debugging failing tests, or following testing conventions. Triggers on: 'write tests', 'add tests', 'test coverage', 'xUnit', 'failing test', 'test pattern', 'TweakDef test', 'TweakEngine test'.
argument-hint	What to test (e.g. 'TweakEngine.Search', 'new service class', 'ConfigExporter')

Testing — RegiLattice

Test Projects

Project	Tests	Covers
tests/RegiLattice.Core.Tests/	2,507+	TweakDef, TweakEngine, RegistrySession, Services, Plugins, Snapshot, Validator, DependencyResolver, Favorites, TweakHistory, ConfigExporter
tests/RegiLattice.CLI.Tests/	434+	CLI argument parsing, ConsoleColorizer
tests/RegiLattice.GUI.Tests/	363+	Theme, PackageManagerValidation, AppIcons

Naming Convention

MethodOrClass_Scenario_ExpectedResult

Examples:

• Search_WithTelemetryQuery_ReturnsPrivacyTweaks
• Register_DuplicateId_ThrowsArgumentException
• DryRun_SetDword_CapturesOpWithoutWrite

Test Skeleton

using Xunit;
using RegiLattice.Core;
using RegiLattice.Core.Models;
using RegiLattice.Core.Registry;

namespace RegiLattice.Core.Tests;

public sealed class MyFeatureTests
{
    [Fact]
    public void Method_HappyPath_ReturnsExpected()
    {
        // Arrange
        var engine = new TweakEngine();
        engine.Register(new TweakDef
        {
            Id = "test-tweak",
            Label = "Test Tweak",
            Category = "Test",
            ApplyOps = [RegOp.SetDword(@"HKCU\Software\Test", "Val", 1)],
            RemoveOps = [RegOp.DeleteValue(@"HKCU\Software\Test", "Val")],
            DetectOps = [RegOp.CheckDword(@"HKCU\Software\Test", "Val", 1)],
        });

        // Act
        var result = engine.GetTweak("test-tweak");

        // Assert
        Assert.NotNull(result);
        Assert.Equal("Test Tweak", result.Label);
    }
}

Critical Testing Rules

Registry safety — always DryRun

var session = new RegistrySession { DryRun = true };
session.SetDword(@"HKCU\Software\RegiLattice\Test", "X", 42);
Assert.Single(session.DryOps);  // captured, never written

HasOperations gate — tweaks without ApplyOps are skipped

// ❌ This tweak will NOT be registered — HasOperations == false
engine.Register(new TweakDef { Id = "t1", Label = "X", Category = "A" });
Assert.Null(engine.GetTweak("t1"));   // silently skipped!

// ✅ Correct — provide at least ApplyOps
engine.Register(new TweakDef { Id = "t1", ...,
    ApplyOps = [RegOp.SetDword(@"HKCU\Test", "V", 1)] });

Never create Form instances in tests

// ❌ BAD — hangs in headless CI
var form = new MainForm();

// ✅ GOOD — test the data model
var theme = Theme.GetTheme("catppuccin-mocha");
Assert.Equal("Catppuccin Mocha", theme!.Name);

Assert.Contains ambiguity — use explicit array

// ❌ BAD — CS0121 ambiguous (HashSet vs SortedSet overload)
Assert.Contains(profile, ["business", "gaming"]);

// ✅ GOOD
Assert.Contains(profile, new[] { "business", "gaming" });

Builtins-heavy tests — share BuiltinsFixture

[Collection("Builtins")]
public sealed class TweakEngineBuiltinsTests
{
    private readonly TweakEngine _engine;

    public TweakEngineBuiltinsTests(BuiltinsFixture fixture)
    {
        _engine = fixture.Engine;
    }
}

Use the shared builtins fixture for tests that only read from RegisterBuiltins() data. Rebuilding the full tweak catalog per test class is unnecessary unless the test explicitly validates registration.

Nullable return guards — ParseArgs() first needs Assert.NotNull()

var args = Program.ParseArgs(["--list"]);
Assert.NotNull(args);
Assert.True(args.ShowList);

Running Tests

# All tests (run per project to avoid cross-assembly races)
dotnet test tests/RegiLattice.Core.Tests/RegiLattice.Core.Tests.csproj --settings tests/.runsettings --blame-hang-timeout 30s
dotnet test tests/RegiLattice.CLI.Tests/RegiLattice.CLI.Tests.csproj --settings tests/.runsettings --blame-hang-timeout 30s
dotnet test tests/RegiLattice.GUI.Tests/RegiLattice.GUI.Tests.csproj --settings tests/.runsettings --blame-hang-timeout 30s

# Single project
dotnet test tests/RegiLattice.Core.Tests --no-build --verbosity normal

# By name filter
dotnet test --no-build --filter "FullyQualifiedName~TweakEngine"

# With coverage
dotnet test --collect:"XPlat Code Coverage"

Coverage Targets

Component	Minimum	Preferred	Notes
TweakDef model	100%	100%	Pure data
TweakEngine	90%+	95%+	Core business logic
RegistrySession	85%+	92%+	Use DryRun for write paths
Services	90%+	95%+	All deterministic logic
GUI theme records	90%+	95%+	Pure data
GUI Forms	60%+	75%+	UI hard to unit test
Overall Core	≥90%	≥95%	Codecov gate enforced — PR below threshold is blocked

Quality Gate — Non-Negotiable

Every test run must satisfy ALL conditions before committing:

Gate	Requirement
Build fatals	0 — hard CI fail
Build warnings	0 — TreatWarningsAsErrors=true; any warning is a build error
Build errors	0 — hard fail
Test failures	0 — all 3,304+ tests must pass
Skipped tests	0 — [Fact(Skip=...)] / [Theory(Skip=...)] are FORBIDDEN
Inline suppressions	0 — #pragma warning disable / [SuppressMessage] / // NOSONAR / // NCA / // NOLINT in test code FORBIDDEN
Waivers / lint ignores	0 — // csharpier-ignore, // coverage: ignore, // HACK: etc. equally forbidden
TODO / FIXME in tests	0 — open a GitHub Issue instead
Line coverage (Core)	≥90% minimum — ≥95% preferred — Codecov enforced; drop below gate = block

# Verify quality gate locally before every commit:
dotnet build RegiLattice.sln -c Release -m:1   # must print: 0 Error(s), 0 Warning(s)
dotnet test tests/RegiLattice.Core.Tests/RegiLattice.Core.Tests.csproj --settings tests/.runsettings --blame-hang-timeout 30s
dotnet test tests/RegiLattice.CLI.Tests/RegiLattice.CLI.Tests.csproj   --settings tests/.runsettings --blame-hang-timeout 30s
dotnet test tests/RegiLattice.GUI.Tests/RegiLattice.GUI.Tests.csproj   --settings tests/.runsettings --blame-hang-timeout 30s

Flaky Test Prevention

Timestamp stripping

// ❌ BAD — DateTime.Now called twice can straddle a second
Assert.Equal(gen.Build(map), File.ReadAllText(path));

// ✅ GOOD
static string StripTs(string s) =>
    Regex.Replace(s, @"\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}", "TIMESTAMP");
Assert.Equal(StripTs(gen.Build(map)), StripTs(File.ReadAllText(path)));

Performance budget comments

// ✅ Required — document tweak count + expected baseline so future changes are deliberate
// Budget: 150ms — ~7,000 tweaks with synonym expansion; ~60ms on dev machine.
Assert.True(sw.ElapsedMilliseconds < 150, $"Search took {sw.ElapsedMilliseconds}ms");

CorporateGuard isolation

public sealed class MyFixture : IDisposable
{
    public MyFixture() => CorporateGuard.StubCorporate = false; // bypass Intune WMI
    public void Dispose() => CorporateGuard.StubCorporate = null;
}

Intentionally Untested (external tools required)

• ChocolateyManager, PipManager, WinGetManager — require installed tool
• ShellRunner — executes real processes
• PackManager async methods — require network
• CorporateGuard WMI paths — environment-dependent