From cf25ee8e8482b5c60fb6fd8b8f0d7e23fcf903d0 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Mon, 12 Sep 2022 14:17:15 +0900
Subject: [PATCH] Add test coverage of storyboard animation start time

---
 .../Formats/LegacyStoryboardDecoderTest.cs    | 19 +++++++++++++++++++
 .../animation-starts-before-alpha.osb         |  5 +++++
 2 files changed, 24 insertions(+)
 create mode 100644 osu.Game.Tests/Resources/animation-starts-before-alpha.osb

diff --git a/osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs b/osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs
index 6e41043b0b..d9e80fa111 100644
--- a/osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs
+++ b/osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs
@@ -97,6 +97,25 @@ namespace osu.Game.Tests.Beatmaps.Formats
             }
         }
 
+        [Test]
+        public void TestCorrectAnimationStartTime()
+        {
+            var decoder = new LegacyStoryboardDecoder();
+
+            using (var resStream = TestResources.OpenResource("animation-starts-before-alpha.osb"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var storyboard = decoder.Decode(stream);
+
+                StoryboardLayer background = storyboard.Layers.Single(l => l.Depth == 3);
+                Assert.AreEqual(1, background.Elements.Count);
+
+                Assert.AreEqual(2000, background.Elements[0].StartTime);
+                // This property should be used in DrawableStoryboardAnimation as a starting point for animation playback.
+                Assert.AreEqual(1000, (background.Elements[0] as StoryboardAnimation)?.EarliestTransformTime);
+            }
+        }
+
         [Test]
         public void TestOutOfOrderStartTimes()
         {
diff --git a/osu.Game.Tests/Resources/animation-starts-before-alpha.osb b/osu.Game.Tests/Resources/animation-starts-before-alpha.osb
new file mode 100644
index 0000000000..ceef204f3f
--- /dev/null
+++ b/osu.Game.Tests/Resources/animation-starts-before-alpha.osb
@@ -0,0 +1,5 @@
+[Events]
+//Storyboard Layer 0 (Background)
+Animation,Background,Centre,"img.jpg",320,240,2,150,LoopForever
+ S,0,1000,1500,0.08 // animation should start playing from this point in time..
+ F,0,2000,,0,1      // .. not this point in time