Add background quality check tests

osu.Game.Tests/Editing/Checks/CheckBackgroundQualityTest.cs

@@ -0,0 +1,130 @@
+// 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.IO;
+using System.Linq;
+using JetBrains.Annotations;
+using Moq;
+using NUnit.Framework;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks;
+using osu.Game.Rulesets.Objects;
+using FileInfo = osu.Game.IO.FileInfo;
+
+namespace osu.Game.Tests.Editing.Checks
+{
+    [TestFixture]
+    public class CheckBackgroundQualityTest
+    {
+        private CheckBackgroundQuality check;
+        private IBeatmap beatmap;
+
+        [SetUp]
+        public void Setup()
+        {
+            check = new CheckBackgroundQuality();
+            beatmap = new Beatmap<HitObject>
+            {
+                BeatmapInfo = new BeatmapInfo
+                {
+                    Metadata = new BeatmapMetadata { BackgroundFile = "abc123.jpg" },
+                    BeatmapSet = new BeatmapSetInfo
+                    {
+                        Files = new List<BeatmapSetFileInfo>(new[]
+                        {
+                            new BeatmapSetFileInfo
+                            {
+                                Filename = "abc123.jpg",
+                                FileInfo = new FileInfo
+                                {
+                                    Hash = "abcdef"
+                                }
+                            }
+                        })
+                    }
+                }
+            };
+        }
+
+        [Test]
+        public void TestBackgroundMissing()
+        {
+            // While this is a problem, it is out of scope for this check and is caught by a different one.
+            beatmap.Metadata.BackgroundFile = null;
+            var mock = getMockWorkingBeatmap(null, System.Array.Empty<byte>());
+
+            Assert.That(check.Run(mock.Object), Is.Empty);
+        }
+
+        [Test]
+        public void TestBackgroundAcceptable()
+        {
+            var mock = getMockWorkingBeatmap(new Texture(1920, 1080));
+
+            Assert.That(check.Run(mock.Object), Is.Empty);
+        }
+
+        [Test]
+        public void TestBackgroundTooHighResolution()
+        {
+            var mock = getMockWorkingBeatmap(new Texture(3840, 2160));
+
+            var issues = check.Run(mock.Object).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackgroundQuality.IssueTemplateTooHighResolution);
+        }
+
+        [Test]
+        public void TestBackgroundLowResolution()
+        {
+            var mock = getMockWorkingBeatmap(new Texture(640, 480));
+
+            var issues = check.Run(mock.Object).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackgroundQuality.IssueTemplateLowResolution);
+        }
+
+        [Test]
+        public void TestBackgroundTooLowResolution()
+        {
+            var mock = getMockWorkingBeatmap(new Texture(100, 100));
+
+            var issues = check.Run(mock.Object).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackgroundQuality.IssueTemplateTooLowResolution);
+        }
+
+        [Test]
+        public void TestBackgroundTooUncompressed()
+        {
+            var mock = getMockWorkingBeatmap(new Texture(1920, 1080), new byte[1024 * 1024 * 3]);
+
+            var issues = check.Run(mock.Object).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackgroundQuality.IssueTemplateTooUncompressed);
+        }
+
+        /// <summary>
+        /// Returns the mock of the working beatmap with the given background and filesize.
+        /// </summary>
+        /// <param name="background">The texture of the background.</param>
+        /// <param name="fileBytes">The bytes that represent the background file.</param>
+        private Mock<IWorkingBeatmap> getMockWorkingBeatmap(Texture background, [CanBeNull] byte[] fileBytes = null)
+        {
+            var stream = new MemoryStream(fileBytes ?? new byte[1024 * 1024]);
+
+            var mock = new Mock<IWorkingBeatmap>();
+            mock.SetupGet(_ => _.Beatmap).Returns(beatmap);
+            mock.SetupGet(_ => _.Background).Returns(background);
+            mock.Setup(_ => _.GetStream(It.IsAny<string>())).Returns(stream);
+
+            return mock;
+        }
+    }
+}