feat(ads/seo/release): v1.2.0 with live Google Ads, isolated ad profile, ads.txt, and SEO/AEO/GEO optimization

tests/Paca.Tests/Core/PlaybackSleepTimerEngineGateTests.cs

@@ -0,0 +1,61 @@
+using System;
+using Paca.Mobile.Core;
+using Xunit;
+
+namespace Paca.Tests.Core;
+
+public class PlaybackSleepTimerEngineGateTests
+{
+    [Fact]
+    public void Gate445_PlaybackSleepTimerEngine_CalculatesVolume_BeforeFade()
+    {
+        var total = TimeSpan.FromMinutes(30);
+        var fade = TimeSpan.FromMinutes(5);
+        var elapsed = TimeSpan.FromMinutes(10);
+
+        var status = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Linear);
+
+        Assert.False(status.IsExpired);
+        Assert.False(status.IsFading);
+        Assert.Equal(1.0, status.VolumeFactor, 2);
+    }
+
+    [Fact]
+    public void Gate446_PlaybackSleepTimerEngine_CalculatesVolume_DuringFade()
+    {
+        var total = TimeSpan.FromMinutes(30);
+        var fade = TimeSpan.FromMinutes(10); // fade starts at 20m
+        var elapsed = TimeSpan.FromMinutes(25); // halfway through 10m fade
+
+        var statusLinear = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Linear);
+        Assert.True(statusLinear.IsFading);
+        Assert.False(statusLinear.IsExpired);
+        Assert.Equal(0.5, statusLinear.VolumeFactor, 2);
+
+        var statusExp = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Exponential);
+        Assert.True(statusExp.VolumeFactor < 0.5); // exponential falls faster
+    }
+
+    [Fact]
+    public void Gate447_PlaybackSleepTimerEngine_TriggersExpiry_AtOrPastTotal()
+    {
+        var total = TimeSpan.FromMinutes(30);
+        var fade = TimeSpan.FromMinutes(5);
+
+        var statusExact = PlaybackSleepTimerEngine.Evaluate(TimeSpan.FromMinutes(30), total, fade, FadeVolumeCurve.Linear);
+        Assert.True(statusExact.IsExpired);
+        Assert.Equal(0.0, statusExact.VolumeFactor);
+
+        var statusPast = PlaybackSleepTimerEngine.Evaluate(TimeSpan.FromMinutes(35), total, fade, FadeVolumeCurve.Linear);
+        Assert.True(statusPast.IsExpired);
+        Assert.Equal(0.0, statusPast.VolumeFactor);
+    }
+
+    [Fact]
+    public void Gate448_PlaybackSleepTimerEngine_BuildsFfmpegAfadeFilter()
+    {
+        var filter = PlaybackSleepTimerEngine.BuildFfmpegFadeOutFilter(totalSec: 1800, fadeDurationSec: 60);
+
+        Assert.Equal("afade=t=out:st=1740:d=60", filter);
+    }
+}