Refactor VideoRecorderSessionHandler.cs into partial class files

[Evangelink]

Overview

Splits the 656-line VideoRecorderSessionHandler.cs into focused partial-class files, matching the pattern already used by FfmpegVideoRecorder in the same directory. This is a pure file reorganization — partial classes compile to the same type, so there are no logic or API changes.

Fixes #9592

Changes

File	Lines	Responsibility
VideoRecorderSessionHandler.cs	172	Fields, constructor, interface properties, session lifecycle (OnTestSessionStarting/Finishing)
VideoRecorderSessionHandler.DataConsumer.cs	102	ConsumeAsync, ResolveTiming, IsTerminal, OutcomeText
VideoRecorderSessionHandler.VideoProduction.cs	179	ProduceVideosAsync, per-test/session production, chapter metadata, EscapeMetadata
VideoRecorderSessionHandler.SegmentPruning.cs	102	TryPruneOldSegments, WarnBufferDropOnce, OverlapsAnyFailedWindow
VideoRecorderSessionHandler.Helpers.cs	143	BuildFileName, Sanitize, PublishArtifactAsync, DeleteDirectoryQuietly, ApplyCommandLineOverrides, nested TestRecord

Verification

• Builds cleanly across netstandard2.0, net8.0, and net9.0 with 0 warnings, 0 errors (including IDE0005 unused-using checks — usings were trimmed per file).
• Each file is under 300 lines.
• Type remains internal sealed partial — no public/internal API surface change.

Acceptance Criteria

• Original file split into focused partial-class files (matching FfmpegVideoRecorder)
• Each new file is under 300 lines
• No breaking changes to internal or public API
• File naming follows the existing TypeName.Concern.cs convention

[Evangelink]

/backport to rel/4.3

[github-actions]

Started backporting to rel/4.3: https://github.com/microsoft/testfx/actions/runs/28736336631

[Copilot]

Pull request overview

This PR is a pure file reorganization that splits the 656-line VideoRecorderSessionHandler.cs into five focused partial-class files, mirroring the existing FfmpegVideoRecorder split in the same directory. Because partial classes compile to the same type, there are no logic or API changes. It resolves issue #9592.

Changes:

• Split VideoRecorderSessionHandler into per-concern partial files (data consumption, video production, segment pruning, helpers) while the primary file retains fields, constructor, interface properties, and session lifecycle.
• Trimmed using directives per file and added the partial keyword; removed the now-unused Microsoft.Testing.Platform import from the primary file.
• No behavioral, public, or internal API changes.

Show a summary per file

File	Description
VideoRecorderSessionHandler.cs	Reduced to fields, constructor, interface properties, and session lifecycle; declaration made partial; unused using removed.
VideoRecorderSessionHandler.DataConsumer.cs	New partial holding ConsumeAsync, ResolveTiming, IsTerminal, OutcomeText.
VideoRecorderSessionHandler.VideoProduction.cs	New partial holding video-production methods and EscapeMetadata.
VideoRecorderSessionHandler.SegmentPruning.cs	New partial holding TryPruneOldSegments, WarnBufferDropOnce, OverlapsAnyFailedWindow.
VideoRecorderSessionHandler.Helpers.cs	New partial holding file-name/artifact helpers, CLI overrides, and nested TestRecord.

Review details

• Files reviewed: 5/5 changed files
• Comments generated: 0
• Review effort level: Medium

[github-actions]

Note

🤖 Automated review by GitHub Copilot. Posted via a maintainer's GitHub token, so it appears under their account — the account owner did not write or approve this content personally. Generated by the Expert Code Review workflow. To request a follow-up action, reply by tagging @copilot directly.

✅ 22/22 dimensions clean — no findings.

This is a well-executed pure file reorganization:

• Partial class split matches the existing FfmpegVideoRecorder.{cs,ProcessManagement.cs,WindowCapture.cs} convention in the same directory.
• No logic changes — code was relocated verbatim; the only functional edit is adding the partial keyword and trimming usings per file (e.g., using Microsoft.Testing.Platform; moved to Helpers.cs where RoslynString is used).
• Thread safety preserved — _stateGate locking pattern spans partial files correctly since they compile to the same type.
• No API surface change — type remains internal sealed partial.
• Cross-TFM #if NET9_0_OR_GREATER for Lock stays in the main file with the field declarations.
• File sizes all under 180 lines — well within the stated 300-line cap.
• Build glob picks up the new .cs files automatically — no .csproj edits needed.

Clean refactoring, no issues.