Add lead-in tests

osu.Game.Tests/Visual/Gameplay/TestCaseLeadIn.cs

@@ -0,0 +1,88 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Beatmaps;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Rulesets;
+using osu.Game.Screens.Play;
+using osu.Game.Tests.Beatmaps;
+using osuTK.Graphics;
+
+namespace osu.Game.Tests.Visual.Gameplay
+{
+    public class TestCaseLeadIn : RateAdjustedBeatmapTestCase
+    {
+        private Ruleset ruleset;
+
+        private LeadInPlayer player;
+
+        [BackgroundDependencyLoader]
+        private void load(RulesetStore rulesets)
+        {
+            Add(new Box
+            {
+                RelativeSizeAxes = Axes.Both,
+                Colour = Color4.Black,
+                Depth = int.MaxValue
+            });
+
+            ruleset = rulesets.AvailableRulesets.First().CreateInstance();
+        }
+
+        [Test]
+        public void TestShortLeadIn()
+        {
+            AddStep("create player", () => loadPlayerWithBeatmap(new TestBeatmap(ruleset.RulesetInfo) { BeatmapInfo = { AudioLeadIn = 1000 } }));
+            AddUntilStep("correct lead-in", () => player.FirstFrameClockTime == 0);
+        }
+
+        [Test]
+        public void TestLongLeadIn()
+        {
+            AddStep("create player", () => loadPlayerWithBeatmap(new TestBeatmap(ruleset.RulesetInfo) { BeatmapInfo = { AudioLeadIn = 10000 } }));
+            AddUntilStep("correct lead-in", () => player.FirstFrameClockTime == player.GameplayStartTime - 10000);
+        }
+
+        private void loadPlayerWithBeatmap(IBeatmap beatmap)
+        {
+            Beatmap.Value = new TestWorkingBeatmap(beatmap, Clock);
+
+            LoadScreen(player = new LeadInPlayer
+            {
+                AllowPause = false,
+                AllowResults = false,
+            });
+        }
+
+        private class LeadInPlayer : Player
+        {
+            public double? FirstFrameClockTime;
+
+            public new GameplayClockContainer GameplayClockContainer => base.GameplayClockContainer;
+
+            public double GameplayStartTime => DrawableRuleset.GameplayStartTime;
+
+            public double GameplayClockTime => GameplayClockContainer.GameplayClock.CurrentTime;
+
+            protected override void UpdateAfterChildren()
+            {
+                base.UpdateAfterChildren();
+                if (!FirstFrameClockTime.HasValue)
+                {
+                    FirstFrameClockTime = GameplayClockContainer.GameplayClock.CurrentTime;
+                    AddInternal(new OsuSpriteText
+                    {
+                        Text = $"GameplayStartTime: {DrawableRuleset.GameplayStartTime} "
+                               + $"LeadInTime: {Beatmap.Value.BeatmapInfo.AudioLeadIn} "
+                               + $"FirstFrameClockTime: {FirstFrameClockTime}"
+                    });
+                }
+            }
+        }
+    }
+}