Add beatmap import and file store tests

osu.Game.Tests/Database/BeatmapImporterTests.cs

@@ -0,0 +1,820 @@
+// 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;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using osu.Framework.Extensions;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Logging;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.IO.Archives;
+using osu.Game.Models;
+using osu.Game.Stores;
+using osu.Game.Tests.Resources;
+using Realms;
+using SharpCompress.Archives;
+using SharpCompress.Archives.Zip;
+using SharpCompress.Common;
+using SharpCompress.Writers.Zip;
+
+#nullable enable
+
+namespace osu.Game.Tests.Database
+{
+    [TestFixture]
+    public class BeatmapImporterTests : RealmTest
+    {
+        [Test]
+        public void TestImportBeatmapThenCleanup()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using (var importer = new BeatmapImporter(realmFactory, storage))
+                using (new RealmRulesetStore(realmFactory, storage))
+                {
+                    ILive<RealmBeatmapSet>? imported;
+
+                    using (var reader = new ZipArchiveReader(TestResources.GetTestBeatmapStream()))
+                        imported = await importer.Import(reader);
+
+                    Assert.AreEqual(1, realmFactory.Context.All<RealmBeatmapSet>().Count());
+
+                    Assert.NotNull(imported);
+                    Debug.Assert(imported != null);
+
+                    imported.PerformWrite(s => s.DeletePending = true);
+
+                    Assert.AreEqual(1, realmFactory.Context.All<RealmBeatmapSet>().Count(s => s.DeletePending));
+                }
+            });
+
+            Logger.Log("Running with no work to purge pending deletions");
+
+            RunTestWithRealm((realmFactory, _) => { Assert.AreEqual(0, realmFactory.Context.All<RealmBeatmapSet>().Count()); });
+        }
+
+        [Test]
+        public void TestImportWhenClosed()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                await LoadOszIntoStore(importer, realmFactory.Context);
+            });
+        }
+
+        [Test]
+        public void TestImportThenDelete()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                deleteBeatmapSet(imported, realmFactory.Context);
+            });
+        }
+
+        [Test]
+        public void TestImportThenDeleteFromStream()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var tempPath = TestResources.GetTestBeatmapForImport();
+
+                ILive<RealmBeatmapSet>? importedSet;
+
+                using (var stream = File.OpenRead(tempPath))
+                {
+                    importedSet = await importer.Import(new ImportTask(stream, Path.GetFileName(tempPath)));
+                    ensureLoaded(realmFactory.Context);
+                }
+
+                Assert.NotNull(importedSet);
+                Debug.Assert(importedSet != null);
+
+                Assert.IsTrue(File.Exists(tempPath), "Stream source file somehow went missing");
+                File.Delete(tempPath);
+
+                var imported = realmFactory.Context.All<RealmBeatmapSet>().First(beatmapSet => beatmapSet.ID == importedSet.ID);
+
+                deleteBeatmapSet(imported, realmFactory.Context);
+            });
+        }
+
+        [Test]
+        public void TestImportThenImport()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+                var importedSecondTime = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                // check the newly "imported" beatmap is actually just the restored previous import. since it matches hash.
+                Assert.IsTrue(imported.ID == importedSecondTime.ID);
+                Assert.IsTrue(imported.Beatmaps.First().ID == importedSecondTime.Beatmaps.First().ID);
+
+                checkBeatmapSetCount(realmFactory.Context, 1);
+                checkSingleReferencedFileCount(realmFactory.Context, 18);
+            });
+        }
+
+        [Test]
+        public void TestImportThenImportWithReZip()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                    string hashBefore = hashFile(temp);
+
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    // zip files differ because different compression or encoder.
+                    Assert.AreNotEqual(hashBefore, hashFile(temp));
+
+                    var importedSecondTime = await importer.Import(new ImportTask(temp));
+
+                    ensureLoaded(realmFactory.Context);
+
+                    Assert.NotNull(importedSecondTime);
+                    Debug.Assert(importedSecondTime != null);
+
+                    // but contents doesn't, so existing should still be used.
+                    Assert.IsTrue(imported.ID == importedSecondTime.ID);
+                    Assert.IsTrue(imported.Beatmaps.First().ID == importedSecondTime.PerformRead(s => s.Beatmaps.First().ID));
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        public void TestImportThenImportWithChangedHashedFile()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                    await createScoreForBeatmap(realmFactory.Context, imported.Beatmaps.First());
+
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    // arbitrary write to hashed file
+                    // this triggers the special BeatmapManager.PreImport deletion/replacement flow.
+                    using (var sw = new FileInfo(Directory.GetFiles(extractedFolder, "*.osu").First()).AppendText())
+                        await sw.WriteLineAsync("// changed");
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    var importedSecondTime = await importer.Import(new ImportTask(temp));
+
+                    ensureLoaded(realmFactory.Context);
+
+                    // check the newly "imported" beatmap is not the original.
+                    Assert.NotNull(importedSecondTime);
+                    Debug.Assert(importedSecondTime != null);
+
+                    Assert.IsTrue(imported.ID != importedSecondTime.ID);
+                    Assert.IsTrue(imported.Beatmaps.First().ID != importedSecondTime.PerformRead(s => s.Beatmaps.First().ID));
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        [Ignore("intentionally broken by import optimisations")]
+        public void TestImportThenImportWithChangedFile()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    // arbitrary write to non-hashed file
+                    using (var sw = new FileInfo(Directory.GetFiles(extractedFolder, "*.mp3").First()).AppendText())
+                        await sw.WriteLineAsync("text");
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    var importedSecondTime = await importer.Import(new ImportTask(temp));
+
+                    ensureLoaded(realmFactory.Context);
+
+                    Assert.NotNull(importedSecondTime);
+                    Debug.Assert(importedSecondTime != null);
+
+                    // check the newly "imported" beatmap is not the original.
+                    Assert.IsTrue(imported.ID != importedSecondTime.ID);
+                    Assert.IsTrue(imported.Beatmaps.First().ID != importedSecondTime.PerformRead(s => s.Beatmaps.First().ID));
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        public void TestImportThenImportWithDifferentFilename()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    // change filename
+                    var firstFile = new FileInfo(Directory.GetFiles(extractedFolder).First());
+                    firstFile.MoveTo(Path.Combine(firstFile.DirectoryName.AsNonNull(), $"{firstFile.Name}-changed{firstFile.Extension}"));
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    var importedSecondTime = await importer.Import(new ImportTask(temp));
+
+                    ensureLoaded(realmFactory.Context);
+
+                    Assert.NotNull(importedSecondTime);
+                    Debug.Assert(importedSecondTime != null);
+
+                    // check the newly "imported" beatmap is not the original.
+                    Assert.IsTrue(imported.ID != importedSecondTime.ID);
+                    Assert.IsTrue(imported.Beatmaps.First().ID != importedSecondTime.PerformRead(s => s.Beatmaps.First().ID));
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        [Ignore("intentionally broken by import optimisations")]
+        public void TestImportCorruptThenImport()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                var firstFile = imported.Files.First();
+
+                long originalLength;
+                using (var stream = storage.GetStream(firstFile.File.StoragePath))
+                    originalLength = stream.Length;
+
+                using (var stream = storage.GetStream(firstFile.File.StoragePath, FileAccess.Write, FileMode.Create))
+                    stream.WriteByte(0);
+
+                var importedSecondTime = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                using (var stream = storage.GetStream(firstFile.File.StoragePath))
+                    Assert.AreEqual(stream.Length, originalLength, "Corruption was not fixed on second import");
+
+                // check the newly "imported" beatmap is actually just the restored previous import. since it matches hash.
+                Assert.IsTrue(imported.ID == importedSecondTime.ID);
+                Assert.IsTrue(imported.Beatmaps.First().ID == importedSecondTime.Beatmaps.First().ID);
+
+                checkBeatmapSetCount(realmFactory.Context, 1);
+                checkSingleReferencedFileCount(realmFactory.Context, 18);
+            });
+        }
+
+        [Test]
+        public void TestRollbackOnFailure()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                int loggedExceptionCount = 0;
+
+                Logger.NewEntry += l =>
+                {
+                    if (l.Target == LoggingTarget.Database && l.Exception != null)
+                        Interlocked.Increment(ref loggedExceptionCount);
+                };
+
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                realmFactory.Context.Write(() => imported.Hash += "-changed");
+
+                checkBeatmapSetCount(realmFactory.Context, 1);
+                checkBeatmapCount(realmFactory.Context, 12);
+                checkSingleReferencedFileCount(realmFactory.Context, 18);
+
+                var brokenTempFilename = TestResources.GetTestBeatmapForImport();
+
+                MemoryStream brokenOsu = new MemoryStream();
+                MemoryStream brokenOsz = new MemoryStream(await File.ReadAllBytesAsync(brokenTempFilename));
+
+                File.Delete(brokenTempFilename);
+
+                using (var outStream = File.Open(brokenTempFilename, FileMode.CreateNew))
+                using (var zip = ZipArchive.Open(brokenOsz))
+                {
+                    zip.AddEntry("broken.osu", brokenOsu, false);
+                    zip.SaveTo(outStream, CompressionType.Deflate);
+                }
+
+                // this will trigger purging of the existing beatmap (online set id match) but should rollback due to broken osu.
+                try
+                {
+                    await importer.Import(new ImportTask(brokenTempFilename));
+                }
+                catch
+                {
+                }
+
+                checkBeatmapSetCount(realmFactory.Context, 1);
+                checkBeatmapCount(realmFactory.Context, 12);
+
+                checkSingleReferencedFileCount(realmFactory.Context, 18);
+
+                Assert.AreEqual(1, loggedExceptionCount);
+
+                File.Delete(brokenTempFilename);
+            });
+        }
+
+        [Test]
+        public void TestImportThenDeleteThenImport()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                deleteBeatmapSet(imported, realmFactory.Context);
+
+                var importedSecondTime = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                // check the newly "imported" beatmap is actually just the restored previous import. since it matches hash.
+                Assert.IsTrue(imported.ID == importedSecondTime.ID);
+                Assert.IsTrue(imported.Beatmaps.First().ID == importedSecondTime.Beatmaps.First().ID);
+            });
+        }
+
+        [Test]
+        public void TestImportThenDeleteThenImportWithOnlineIDsMissing()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var imported = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                realmFactory.Context.Write(() =>
+                {
+                    foreach (var b in imported.Beatmaps)
+                        b.OnlineID = null;
+                });
+
+                deleteBeatmapSet(imported, realmFactory.Context);
+
+                var importedSecondTime = await LoadOszIntoStore(importer, realmFactory.Context);
+
+                // check the newly "imported" beatmap has been reimported due to mismatch (even though hashes matched)
+                Assert.IsTrue(imported.ID != importedSecondTime.ID);
+                Assert.IsTrue(imported.Beatmaps.First().ID != importedSecondTime.Beatmaps.First().ID);
+            });
+        }
+
+        [Test]
+        public void TestImportWithDuplicateBeatmapIDs()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var metadata = new RealmBeatmapMetadata
+                {
+                    Artist = "SomeArtist",
+                    Author = "SomeAuthor"
+                };
+
+                var ruleset = realmFactory.Context.All<RealmRuleset>().First();
+
+                var toImport = new RealmBeatmapSet
+                {
+                    OnlineID = 1,
+                    Beatmaps =
+                    {
+                        new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata)
+                        {
+                            OnlineID = 2,
+                        },
+                        new RealmBeatmap(ruleset, new RealmBeatmapDifficulty(), metadata)
+                        {
+                            OnlineID = 2,
+                            Status = BeatmapSetOnlineStatus.Loved,
+                        }
+                    }
+                };
+
+                var imported = await importer.Import(toImport);
+
+                Assert.NotNull(imported);
+                Debug.Assert(imported != null);
+
+                Assert.AreEqual(null, imported.PerformRead(s => s.Beatmaps[0].OnlineID));
+                Assert.AreEqual(null, imported.PerformRead(s => s.Beatmaps[1].OnlineID));
+            });
+        }
+
+        [Test]
+        public void TestImportWhenFileOpen()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+                using (File.OpenRead(temp))
+                    await importer.Import(temp);
+                ensureLoaded(realmFactory.Context);
+                File.Delete(temp);
+                Assert.IsFalse(File.Exists(temp), "We likely held a read lock on the file when we shouldn't");
+            });
+        }
+
+        [Test]
+        public void TestImportWithDuplicateHashes()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.AddEntry("duplicate.osu", Directory.GetFiles(extractedFolder, "*.osu").First());
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    await importer.Import(temp);
+
+                    ensureLoaded(realmFactory.Context);
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        public void TestImportNestedStructure()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                string subfolder = Path.Combine(extractedFolder, "subfolder");
+
+                Directory.CreateDirectory(subfolder);
+
+                try
+                {
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(subfolder);
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    var imported = await importer.Import(new ImportTask(temp));
+
+                    Assert.NotNull(imported);
+                    Debug.Assert(imported != null);
+
+                    ensureLoaded(realmFactory.Context);
+
+                    Assert.IsFalse(imported.PerformRead(s => s.Files.Any(f => f.Filename.Contains("subfolder"))), "Files contain common subfolder");
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        public void TestImportWithIgnoredDirectoryInArchive()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                string dataFolder = Path.Combine(extractedFolder, "actual_data");
+                string resourceForkFolder = Path.Combine(extractedFolder, "__MACOSX");
+                string resourceForkFilePath = Path.Combine(resourceForkFolder, ".extracted");
+
+                Directory.CreateDirectory(dataFolder);
+                Directory.CreateDirectory(resourceForkFolder);
+
+                using (var resourceForkFile = File.CreateText(resourceForkFilePath))
+                {
+                    await resourceForkFile.WriteLineAsync("adding content so that it's not empty");
+                }
+
+                try
+                {
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(dataFolder);
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    var imported = await importer.Import(new ImportTask(temp));
+
+                    Assert.NotNull(imported);
+                    Debug.Assert(imported != null);
+
+                    ensureLoaded(realmFactory.Context);
+
+                    Assert.IsFalse(imported.PerformRead(s => s.Files.Any(f => f.Filename.Contains("__MACOSX"))), "Files contain resource fork folder, which should be ignored");
+                    Assert.IsFalse(imported.PerformRead(s => s.Files.Any(f => f.Filename.Contains("actual_data"))), "Files contain common subfolder");
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
+        [Test]
+        public void TestUpdateBeatmapInfo()
+        {
+            RunTestWithRealmAsync(async (realmFactory, storage) =>
+            {
+                using var importer = new BeatmapImporter(realmFactory, storage);
+                using var store = new RealmRulesetStore(realmFactory, storage);
+
+                var temp = TestResources.GetTestBeatmapForImport();
+                await importer.Import(temp);
+
+                // Update via the beatmap, not the beatmap info, to ensure correct linking
+                RealmBeatmapSet setToUpdate = realmFactory.Context.All<RealmBeatmapSet>().First();
+
+                var beatmapToUpdate = setToUpdate.Beatmaps.First();
+
+                realmFactory.Context.Write(() => beatmapToUpdate.DifficultyName = "updated");
+
+                RealmBeatmap updatedInfo = realmFactory.Context.All<RealmBeatmap>().First(b => b.ID == beatmapToUpdate.ID);
+                Assert.That(updatedInfo.DifficultyName, Is.EqualTo("updated"));
+            });
+        }
+
+        public static async Task<RealmBeatmapSet?> LoadQuickOszIntoOsu(BeatmapImporter importer, Realm realm)
+        {
+            var temp = TestResources.GetQuickTestBeatmapForImport();
+
+            var importedSet = await importer.Import(new ImportTask(temp));
+
+            Assert.NotNull(importedSet);
+
+            ensureLoaded(realm);
+
+            waitForOrAssert(() => !File.Exists(temp), "Temporary file still exists after standard import", 5000);
+
+            return realm.All<RealmBeatmapSet>().FirstOrDefault(beatmapSet => beatmapSet.ID == importedSet!.ID);
+        }
+
+        public static async Task<RealmBeatmapSet> LoadOszIntoStore(BeatmapImporter importer, Realm realm, string? path = null, bool virtualTrack = false)
+        {
+            var temp = path ?? TestResources.GetTestBeatmapForImport(virtualTrack);
+
+            var importedSet = await importer.Import(new ImportTask(temp));
+
+            Assert.NotNull(importedSet);
+            Debug.Assert(importedSet != null);
+
+            ensureLoaded(realm);
+
+            waitForOrAssert(() => !File.Exists(temp), "Temporary file still exists after standard import", 5000);
+
+            return realm.All<RealmBeatmapSet>().First(beatmapSet => beatmapSet.ID == importedSet.ID);
+        }
+
+        private void deleteBeatmapSet(RealmBeatmapSet imported, Realm realm)
+        {
+            realm.Write(() => imported.DeletePending = true);
+
+            checkBeatmapSetCount(realm, 0);
+            checkBeatmapSetCount(realm, 1, true);
+
+            Assert.IsTrue(realm.All<RealmBeatmapSet>().First(_ => true).DeletePending);
+        }
+
+        private static Task createScoreForBeatmap(Realm realm, RealmBeatmap beatmap)
+        {
+            // TODO: reimplement when we have score support in realm.
+            // return ImportScoreTest.LoadScoreIntoOsu(osu, new ScoreInfo
+            // {
+            //     OnlineScoreID = 2,
+            //     Beatmap = beatmap,
+            //     BeatmapInfoID = beatmap.ID
+            // }, new ImportScoreTest.TestArchiveReader());
+
+            return Task.CompletedTask;
+        }
+
+        private static void checkBeatmapSetCount(Realm realm, int expected, bool includeDeletePending = false)
+        {
+            Assert.AreEqual(expected, includeDeletePending
+                ? realm.All<RealmBeatmapSet>().Count()
+                : realm.All<RealmBeatmapSet>().Count(s => !s.DeletePending));
+        }
+
+        private static string hashFile(string filename)
+        {
+            using (var s = File.OpenRead(filename))
+                return s.ComputeMD5Hash();
+        }
+
+        private static void checkBeatmapCount(Realm realm, int expected)
+        {
+            Assert.AreEqual(expected, realm.All<RealmBeatmap>().Where(_ => true).ToList().Count);
+        }
+
+        private static void checkSingleReferencedFileCount(Realm realm, int expected)
+        {
+            int singleReferencedCount = 0;
+
+            foreach (var f in realm.All<RealmFile>())
+            {
+                if (f.BacklinksCount == 1)
+                    singleReferencedCount++;
+            }
+
+            Assert.AreEqual(expected, singleReferencedCount);
+        }
+
+        private static void ensureLoaded(Realm realm, int timeout = 60000)
+        {
+            IQueryable<RealmBeatmapSet>? resultSets = null;
+
+            waitForOrAssert(() => (resultSets = realm.All<RealmBeatmapSet>().Where(s => s.OnlineID == 241526)).Any(),
+                @"BeatmapSet did not import to the database in allocated time.", timeout);
+
+            // ensure we were stored to beatmap database backing...
+            Assert.IsTrue(resultSets?.Count() == 1, $@"Incorrect result count found ({resultSets?.Count()} but should be 1).");
+
+            IEnumerable<RealmBeatmapSet> queryBeatmapSets() => realm.All<RealmBeatmapSet>().Where(s => !s.DeletePending && s.OnlineID == 241526);
+
+            var set = queryBeatmapSets().First();
+
+            // ReSharper disable once PossibleUnintendedReferenceComparison
+            IEnumerable<RealmBeatmap> queryBeatmaps() => realm.All<RealmBeatmap>().Where(s => s.BeatmapSet != null && s.BeatmapSet == set);
+
+            waitForOrAssert(() => queryBeatmaps().Count() == 12, @"Beatmaps did not import to the database in allocated time", timeout);
+            waitForOrAssert(() => queryBeatmapSets().Count() == 1, @"BeatmapSet did not import to the database in allocated time", timeout);
+
+            int countBeatmapSetBeatmaps = 0;
+            int countBeatmaps = 0;
+
+            waitForOrAssert(() =>
+                    (countBeatmapSetBeatmaps = queryBeatmapSets().First().Beatmaps.Count) ==
+                    (countBeatmaps = queryBeatmaps().Count()),
+                $@"Incorrect database beatmap count post-import ({countBeatmaps} but should be {countBeatmapSetBeatmaps}).", timeout);
+
+            foreach (RealmBeatmap b in set.Beatmaps)
+                Assert.IsTrue(set.Beatmaps.Any(c => c.OnlineID == b.OnlineID));
+            Assert.IsTrue(set.Beatmaps.Count > 0);
+        }
+
+        private static void waitForOrAssert(Func<bool> result, string failureMessage, int timeout = 60000)
+        {
+            const int sleep = 200;
+
+            while (timeout > 0)
+            {
+                Thread.Sleep(sleep);
+                timeout -= sleep;
+
+                if (result())
+                    return;
+            }
+
+            Assert.Fail(failureMessage);
+        }
+    }
+}

osu.Game/Database/IPostImports.cs

@@ -4,6 +4,8 @@
 using System;
 using System.Collections.Generic;
 
+#nullable enable
+
 namespace osu.Game.Database
 {
     public interface IPostImports<out TModel>
@@ -12,6 +14,6 @@ namespace osu.Game.Database
         /// <summary>
         /// Fired when the user requests to view the resulting import.
         /// </summary>
-        public Action<IEnumerable<ILive<TModel>>> PostImport { set; }
+        public Action<IEnumerable<ILive<TModel>>>? PostImport { set; }
     }
 }

osu.Game/Stores/ArchiveModelImporter.cs

@@ -64,7 +64,7 @@ namespace osu.Game.Stores
         /// <summary>
         /// Fired when the user requests to view the resulting import.
         /// </summary>
-        public Action<IEnumerable<ILive<TModel>>>? PresentImport;
+        public Action<IEnumerable<ILive<TModel>>>? PostImport { get; set; }
 
         /// <summary>
         /// Set an endpoint for notifications to be posted to.
@@ -172,12 +172,12 @@ namespace osu.Game.Stores
                     ? $"Imported {imported.First()}!"
                     : $"Imported {imported.Count} {HumanisedModelName}s!";
 
-                if (imported.Count > 0 && PresentImport != null)
+                if (imported.Count > 0 && PostImport != null)
                 {
                     notification.CompletionText += " Click to view.";
                     notification.CompletionClickAction = () =>
                     {
-                        PresentImport?.Invoke(imported);
+                        PostImport?.Invoke(imported);
                         return true;
                     };
                 }