diff --git a/osu.Game.Rulesets.Osu.Tests/Editor/Checks/CheckLowDiffOverlapsTest.cs b/osu.Game.Rulesets.Osu.Tests/Editor/Checks/CheckLowDiffOverlapsTest.cs
new file mode 100644
index 0000000000..fd17d11d10
--- /dev/null
+++ b/osu.Game.Rulesets.Osu.Tests/Editor/Checks/CheckLowDiffOverlapsTest.cs
@@ -0,0 +1,260 @@
+// 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.Collections.Generic;
+using System.Linq;
+using Moq;
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu.Edit.Checks;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Tests.Beatmaps;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
+{
+    [TestFixture]
+    public class CheckLowDiffOverlapsTest
+    {
+        private CheckLowDiffOverlaps check;
+
+        [SetUp]
+        public void Setup()
+        {
+            check = new CheckLowDiffOverlaps();
+        }
+
+        [Test]
+        public void TestNoOverlapFarApart()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 500, Position = new Vector2(200, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestNoOverlapClose()
+        {
+            assertShouldProbablyOverlap(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 167, Position = new Vector2(200, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestNoOverlapTooClose()
+        {
+            assertShouldOverlap(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 100, Position = new Vector2(200, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestNoOverlapTooCloseExpert()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 100, Position = new Vector2(200, 0) }
+                }
+            }, DifficultyRating.Expert);
+        }
+
+        [Test]
+        public void TestOverlapClose()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 167, Position = new Vector2(20, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestOverlapFarApart()
+        {
+            assertShouldNotOverlap(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 500, Position = new Vector2(20, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestAlmostOverlapFarApart()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    // Default circle diameter is 128 px, but part of that is the fade/border of the circle.
+                    // We want this to only be a problem when it actually looks like an overlap.
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 500, Position = new Vector2(125, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestAlmostNotOverlapFarApart()
+        {
+            assertShouldNotOverlap(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 500, Position = new Vector2(110, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestOverlapFarApartExpert()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 500, Position = new Vector2(20, 0) }
+                }
+            }, DifficultyRating.Expert);
+        }
+
+        [Test]
+        public void TestOverlapTooFarApart()
+        {
+            // Far apart enough to where the objects are not visible at the same time, and so overlapping is fine.
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 0, Position = new Vector2(0) },
+                    new HitCircle { StartTime = 2000, Position = new Vector2(20, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestSliderTailOverlapFarApart()
+        {
+            assertShouldNotOverlap(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    getSliderMock(startTime: 0, endTime: 500, startPosition: new Vector2(0, 0), endPosition: new Vector2(100, 0)).Object,
+                    new HitCircle { StartTime = 1000, Position = new Vector2(120, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestSliderTailOverlapClose()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    getSliderMock(startTime: 0, endTime: 900, startPosition: new Vector2(0, 0), endPosition: new Vector2(100, 0)).Object,
+                    new HitCircle { StartTime = 1000, Position = new Vector2(120, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestSliderTailNoOverlapFarApart()
+        {
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    getSliderMock(startTime: 0, endTime: 500, startPosition: new Vector2(0, 0), endPosition: new Vector2(100, 0)).Object,
+                    new HitCircle { StartTime = 1000, Position = new Vector2(300, 0) }
+                }
+            });
+        }
+
+        [Test]
+        public void TestSliderTailNoOverlapClose()
+        {
+            // If these were circles they would need to overlap, but overlapping with slider tails is not required.
+            assertOk(new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    getSliderMock(startTime: 0, endTime: 900, startPosition: new Vector2(0, 0), endPosition: new Vector2(100, 0)).Object,
+                    new HitCircle { StartTime = 1000, Position = new Vector2(300, 0) }
+                }
+            });
+        }
+
+        private Mock<Slider> getSliderMock(double startTime, double endTime, Vector2 startPosition, Vector2 endPosition)
+        {
+            var mockSlider = new Mock<Slider>();
+            mockSlider.SetupGet(s => s.StartTime).Returns(startTime);
+            mockSlider.SetupGet(s => s.Position).Returns(startPosition);
+            mockSlider.SetupGet(s => s.EndPosition).Returns(endPosition);
+            mockSlider.As<IHasDuration>().Setup(d => d.EndTime).Returns(endTime);
+
+            return mockSlider;
+        }
+
+        private void assertOk(IBeatmap beatmap, DifficultyRating difficultyRating = DifficultyRating.Easy)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), difficultyRating);
+            Assert.That(check.Run(context), Is.Empty);
+        }
+
+        private void assertShouldProbablyOverlap(IBeatmap beatmap, int count = 1)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), DifficultyRating.Easy);
+            var issues = check.Run(context).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(count));
+            Assert.That(issues.All(issue => issue.Template is CheckLowDiffOverlaps.IssueTemplateShouldProbablyOverlap));
+        }
+
+        private void assertShouldOverlap(IBeatmap beatmap, int count = 1)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), DifficultyRating.Easy);
+            var issues = check.Run(context).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(count));
+            Assert.That(issues.All(issue => issue.Template is CheckLowDiffOverlaps.IssueTemplateShouldOverlap));
+        }
+
+        private void assertShouldNotOverlap(IBeatmap beatmap, int count = 1)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), DifficultyRating.Easy);
+            var issues = check.Run(context).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(count));
+            Assert.That(issues.All(issue => issue.Template is CheckLowDiffOverlaps.IssueTemplateShouldNotOverlap));
+        }
+    }
+}
diff --git a/osu.Game.Rulesets.Osu.Tests/osu.Game.Rulesets.Osu.Tests.csproj b/osu.Game.Rulesets.Osu.Tests/osu.Game.Rulesets.Osu.Tests.csproj
index ebe642803b..1efd19f49d 100644
--- a/osu.Game.Rulesets.Osu.Tests/osu.Game.Rulesets.Osu.Tests.csproj
+++ b/osu.Game.Rulesets.Osu.Tests/osu.Game.Rulesets.Osu.Tests.csproj
@@ -3,6 +3,7 @@
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.10.0" />
+    <PackageReference Include="Moq" Version="4.16.1" />
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.17.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />