Fixtures

Each fixture starts and owns one Godot engine for the tests that use it.

Type	Use
HeadlessFixture	Starts Godot with --headless; the usual fixture for game logic, scenes, resources and CI
Fixture	Starts Godot with rendering, for tests that need a display, rendered frames or windows
FixtureBase	Base class; derive from it to pass other Godot arguments
HeadlessCollection, RenderingCollection	Non-parallel xUnit collections that share one fixture

FixtureBase

public abstract class FixtureBase : IDisposable

Package: 2dog.engine
Namespace: twodog.Testing

The constructor resolves the Godot project directory, preloads game assemblies, and starts the engine without its configured main scene.

Constructor

protected FixtureBase(params string[] cmdLineArgs)

Passes each argument to Godot unchanged. One process supports either headless or rendering fixtures, not both. The constructor rejects a change from one mode to the other.

Properties

Property	Type	Description
Engine	twodog.Engine	Engine owned by the fixture
GodotInstance	Godot.GodotInstance	Borrowed compatibility handle
Tree	Godot.SceneTree	Active scene tree
Errors	twodog.GodotErrorLog	Errors and warnings Godot reported and no test consumed yet
Input	twodog.Testing.TestInput	Input server events, viewport routing and control-position clicks

Input

Use Input.Click(control) to aim at a control through its viewport's input router. Foreground controls and viewport input suppression keep their normal behavior. PushToViewport routes custom events locally. Send uses the input server and also updates the global polling state. Call these on the engine's owner thread. See Simulating Input for examples and the distinction between modes.

Errors

The fixture starts its engine with CaptureErrors enabled. Every error and warning that Godot reports goes to Errors: push_error, failed engine checks, and exceptions that Godot catches in C# callbacks. With 2dog.xunit or 2dog.nunit, a test fails if any errors or warnings remain in Errors after it. A test that expects an error consumes it and asserts its text:

godot.Errors.Expect("Health must not be negative");

Drain() returns and clears the log without asserting anything.

Dispose

public void Dispose()

Disposes the Engine that the fixture owns. Let the test framework call this at the end of the fixture lifetime.

HeadlessFixture

public class HeadlessFixture : FixtureBase

Starts Godot with --headless. Use it for game logic, scenes, resources and CI.

Fixture

public class Fixture : FixtureBase

Starts Godot with rendering enabled, for tests that need a display, rendered frames or window behavior.

xUnit Collections

public class HeadlessCollection : ICollectionFixture<HeadlessFixture>
public class RenderingCollection : ICollectionFixture<Fixture>

Package: 2dog.xunit
Namespace: twodog.Testing.Xunit

Each collection is non-parallel and shares one fixture across its test classes. The package compiles the definitions into your test assembly so xUnit can discover them. Remove the nodes and other state that each test adds, so that they do not affect the next test.

using twodog.Testing;
using twodog.Testing.Xunit;
using Xunit;

[Collection<HeadlessCollection>]
public class SceneTests(HeadlessFixture godot)
{
    [Fact]
    public void SceneTree_IsRunning() => Assert.NotNull(godot.Tree.Root);
}

Custom collection

To pass other Godot arguments, derive from FixtureBase. Define a non-parallel collection for the new fixture, because Godot is not thread-safe.

using twodog.Testing;
using Xunit;

public class OpenGl3Fixture()
    : FixtureBase("--rendering-driver", "opengl3");

[CollectionDefinition(nameof(OpenGl3Collection), DisableParallelization = true)]
public class OpenGl3Collection : ICollectionFixture<OpenGl3Fixture>;