Upgraded to .NET 10 (#1147)

app/Tests/Tools/Mail/MailboxIndexerTests.cs

@@ -49,7 +49,7 @@ public sealed class MailboxIndexerTests
         var text = MailTextBuilder.Build(MailSummaryReader.ReadTextSource(summary, new MailTextParts(null, "Please review the attached report before the board meeting.")));
         var record = MailboxIndexer.CreateMailRecord(MAIL_ID, summary, text with { Body = "Please review the attached report." }, [], "HASH", LOCATION, FOUND_AT);
 
-        Assert.Multiple(() =>
+        using (Assert.EnterMultipleScope())
         {
             Assert.That(record.Parts.Select(part => part.Kind), Is.EqualTo(new[] { MailPartKind.HEADERS, MailPartKind.BODY }));
             Assert.That(record.Parts[0].Text, Is.EqualTo(MailSummaryReader.ReadHeaderBlock(headers)));
@@ -60,7 +60,7 @@ public sealed class MailboxIndexerTests
             Assert.That(record.ReceivedAtUtc, Is.EqualTo(record.SentAtUtc), "Without the arrival time of the server, the date of the sender stands in.");
             Assert.That(record.FirstSeenUtc, Is.EqualTo(FOUND_AT));
             Assert.That(record.Locations, Is.EqualTo(new[] { LOCATION }));
-        });
+        }
     }
 
     [Test]
@@ -76,13 +76,13 @@ public sealed class MailboxIndexerTests
         var text = MailTextBuilder.Build(MailSummaryReader.ReadTextSource(summary, null));
         var record = MailboxIndexer.CreateMailRecord(MAIL_ID, summary, text, [], "HASH", LOCATION, FOUND_AT);
 
-        Assert.Multiple(() =>
+        using (Assert.EnterMultipleScope())
         {
             Assert.That(record.Parts.Select(part => part.Kind), Is.EqualTo(new[] { MailPartKind.HEADERS }), "Something of the encrypted content is kept.");
             Assert.That(record.EncryptionKind, Is.EqualTo(MailEncryptionKind.SMIME));
             Assert.That(record.ReceivedAtUtc, Is.EqualTo(new DateTimeOffset(2026, 9, 30, 13, 0, 5, TimeSpan.Zero)));
             Assert.That(record.ReceivedAtUtc.Offset, Is.EqualTo(TimeSpan.Zero));
-        });
+        }
     }
 
     [Test]
@@ -102,12 +102,12 @@ public sealed class MailboxIndexerTests
             MailAttachmentText.WithoutText(video, "keynote.mp4", MailPartTextState.UNSUPPORTED_TYPE),
         ], "HASH", LOCATION, FOUND_AT);
 
-        Assert.Multiple(() =>
+        using (Assert.EnterMultipleScope())
         {
             Assert.That(record.Parts.Select(part => part.Kind), Is.EqualTo(new[] { MailPartKind.HEADERS, MailPartKind.BODY, MailPartKind.ATTACHMENT, MailPartKind.ATTACHMENT }));
             Assert.That(record.Parts[2], Is.EqualTo(new MailPartRecord(MailPartKind.ATTACHMENT, "board-report.pdf", "application/pdf", 4096, "Revenue rose by four percent.", MailPartTextState.EXTRACTED)));
             Assert.That(record.Parts[3], Is.EqualTo(new MailPartRecord(MailPartKind.ATTACHMENT, "keynote.mp4", "video/mp4", 80_000_000, null, MailPartTextState.UNSUPPORTED_TYPE)), "An attachment without text is still an attachment, and a search for mails with attachments has to find it.");
-        });
+        }
     }
 
     /// <remarks>
@@ -136,12 +136,12 @@ public sealed class MailboxIndexerTests
         await foreach (var chunk in MailboxIndexer.StreamMailChunksAsync(chunker, mailText, attachments, new ChunkingOptions(100, 0), embeddingProvider, CancellationToken.None))
             chunks.Add(chunk);
 
-        Assert.Multiple(() =>
+        using (Assert.EnterMultipleScope())
         {
             Assert.That(chunks.Select(chunk => chunk.AttachmentPosition), Is.EqualTo(new int?[] { null, 1 }), "The text of the mail is no attachment, and the report is the second attachment, after the video without text.");
             Assert.That(chunks[1].Text, Does.StartWith("Attachment: board-report.pdf"));
             Assert.That((chunks[1].PageNumber, chunks[1].EndPageNumber), Is.EqualTo(((int?)1, (int?)2)), "The chunk keeps the pages of the report it spans.");
-        });
+        }
     }
 
     private static BodyPartBasic Attachment(string mediaType, string mediaSubtype, uint octets) => new(new ContentType(mediaType, mediaSubtype), PART_SPECIFIER)