refactor(app): define ordered composition contract

tests/AcDream.App.Tests/Composition/GameWindowCompositionPipelineTests.cs

@@ -0,0 +1,189 @@
+using AcDream.App.Composition;
+
+namespace AcDream.App.Tests.Composition;
+
+public sealed class GameWindowCompositionPipelineTests
+{
+    [Theory]
+    [InlineData(1)]
+    [InlineData(2)]
+    [InlineData(3)]
+    [InlineData(4)]
+    [InlineData(5)]
+    [InlineData(6)]
+    [InlineData(7)]
+    [InlineData(8)]
+    [InlineData(9)]
+    public void FailureRunsExactlyTheRequiredPrefix(int failingPhase)
+    {
+        var phases = new RecordingPhases(failingPhase);
+        GameWindowCompositionPipeline<Token, Token, Token, Token, Token, Token, Token, Token, Token>
+            pipeline = phases.BuildPipeline();
+
+        Assert.Throws<InvalidOperationException>(() => pipeline.Run(phases.Platform));
+
+        Assert.Equal(
+            Enumerable.Range(1, failingPhase).Select(value => $"phase-{value}"),
+            phases.Calls);
+    }
+
+    [Fact]
+    public void SuccessPassesExactResultsAndStartsSessionLast()
+    {
+        var phases = new RecordingPhases(failingPhase: 0);
+        GameWindowCompositionPipeline<Token, Token, Token, Token, Token, Token, Token, Token, Token>
+            pipeline = phases.BuildPipeline();
+
+        pipeline.Run(phases.Platform);
+
+        Assert.Equal(
+            Enumerable.Range(1, 9).Select(value => $"phase-{value}"),
+            phases.Calls);
+        Assert.Equal("phase-9", phases.Calls[^1]);
+    }
+
+    private sealed record Token(int Phase);
+
+    private sealed class RecordingPhases(int failingPhase) :
+        IHostInputCameraCompositionPhase<Token, Token>,
+        IContentEffectsAudioCompositionPhase<Token, Token, Token>,
+        ISettingsDevToolsCompositionPhase<Token, Token, Token, Token>,
+        IWorldRenderCompositionPhase<Token, Token, Token, Token>,
+        IInteractionUiCompositionPhase<Token, Token, Token, Token, Token>,
+        ILivePresentationCompositionPhase<Token, Token, Token, Token, Token>,
+        ISessionPlayerCompositionPhase<Token, Token, Token, Token, Token, Token>,
+        IFrameRootCompositionPhase<Token, Token, Token, Token, Token, Token, Token>,
+        ISessionStartCompositionPhase<Token>
+    {
+        public Token Platform { get; } = new(0);
+        public List<string> Calls { get; } = [];
+
+        private readonly Token _host = new(1);
+        private readonly Token _content = new(2);
+        private readonly Token _settings = new(3);
+        private readonly Token _world = new(4);
+        private readonly Token _interaction = new(5);
+        private readonly Token _live = new(6);
+        private readonly Token _session = new(7);
+        private readonly Token _frame = new(8);
+
+        public GameWindowCompositionPipeline<Token, Token, Token, Token, Token, Token, Token, Token, Token>
+            BuildPipeline() => new(this, this, this, this, this, this, this, this, this);
+
+        Token IHostInputCameraCompositionPhase<Token, Token>.Compose(Token platform)
+        {
+            Assert.Same(Platform, platform);
+            Record(1);
+            return _host;
+        }
+
+        Token IContentEffectsAudioCompositionPhase<Token, Token, Token>.Compose(
+            Token platform,
+            Token host)
+        {
+            Assert.Same(Platform, platform);
+            Assert.Same(_host, host);
+            Record(2);
+            return _content;
+        }
+
+        Token ISettingsDevToolsCompositionPhase<Token, Token, Token, Token>.Compose(
+            Token platform,
+            Token host,
+            Token content)
+        {
+            Assert.Same(Platform, platform);
+            Assert.Same(_host, host);
+            Assert.Same(_content, content);
+            Record(3);
+            return _settings;
+        }
+
+        Token IWorldRenderCompositionPhase<Token, Token, Token, Token>.Compose(
+            Token platform,
+            Token content,
+            Token settings)
+        {
+            Assert.Same(Platform, platform);
+            Assert.Same(_content, content);
+            Assert.Same(_settings, settings);
+            Record(4);
+            return _world;
+        }
+
+        Token IInteractionUiCompositionPhase<Token, Token, Token, Token, Token>.Compose(
+            Token host,
+            Token content,
+            Token settings,
+            Token world)
+        {
+            Assert.Same(_host, host);
+            Assert.Same(_content, content);
+            Assert.Same(_settings, settings);
+            Assert.Same(_world, world);
+            Record(5);
+            return _interaction;
+        }
+
+        Token ILivePresentationCompositionPhase<Token, Token, Token, Token, Token>.Compose(
+            Token host,
+            Token content,
+            Token world,
+            Token interaction)
+        {
+            Assert.Same(_host, host);
+            Assert.Same(_content, content);
+            Assert.Same(_world, world);
+            Assert.Same(_interaction, interaction);
+            Record(6);
+            return _live;
+        }
+
+        Token ISessionPlayerCompositionPhase<Token, Token, Token, Token, Token, Token>.Compose(
+            Token host,
+            Token content,
+            Token world,
+            Token interaction,
+            Token live)
+        {
+            Assert.Same(_host, host);
+            Assert.Same(_content, content);
+            Assert.Same(_world, world);
+            Assert.Same(_interaction, interaction);
+            Assert.Same(_live, live);
+            Record(7);
+            return _session;
+        }
+
+        Token IFrameRootCompositionPhase<Token, Token, Token, Token, Token, Token, Token>.Compose(
+            Token host,
+            Token settings,
+            Token world,
+            Token interaction,
+            Token live,
+            Token session)
+        {
+            Assert.Same(_host, host);
+            Assert.Same(_settings, settings);
+            Assert.Same(_world, world);
+            Assert.Same(_interaction, interaction);
+            Assert.Same(_live, live);
+            Assert.Same(_session, session);
+            Record(8);
+            return _frame;
+        }
+
+        void ISessionStartCompositionPhase<Token>.Start(Token frame)
+        {
+            Assert.Same(_frame, frame);
+            Record(9);
+        }
+
+        private void Record(int phase)
+        {
+            Calls.Add($"phase-{phase}");
+            if (failingPhase == phase)
+                throw new InvalidOperationException($"phase {phase} failed");
+        }
+    }
+}