Adding Data, DataObject, FileDrop and Text tests to ClipboardCoreTests

[LeafShi1]

Related #13331

Proposed changes

• Adding Data, DataObject, FileDrop and Text tests to ClipboardCoreTests

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.69074%. Comparing base (08485db) to head (ae954c4).
Report is 11 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #13645         +/-   ##
===================================================
+ Coverage   76.60828%   76.69074%   +0.08246%     
===================================================
  Files           3253        3255          +2     
  Lines         640996      641599        +603     
  Branches       47439       47490         +51     
===================================================
+ Hits          491056      492047        +991     
+ Misses        146290      145888        -402     
- Partials        3650        3664         +14     

Flag	Coverage Δ
Debug	76.69074% <ø> (+0.08246%)	⬆️
integration	18.98826% <ø> (-0.00558%)	⬇️
production	51.20523% <ø> (+0.13622%)	⬆️
test	97.41503% <ø> (+0.00328%)	⬆️
unit	48.58591% <ø> (+0.13901%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[Copilot]

Pull Request Overview

This PR expands ClipboardCoreTests by adding comprehensive tests for various SetData scenarios, including custom formats, object data, file drops, image/bitmap/metafile handling, and multiple text formats. It also updates the test project to reference drawing and GDI+ libraries and includes bitmap assets for testing.

• Introduces TheoryData and parameterized tests for custom data formats and exception types
• Adds tests for SetDataObject overloads, file drop lists, images, metafiles, and text formats
• Updates .csproj to reference System.Drawing.Common and GDI+ and to include bitmap fixtures

Reviewed Changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated 1 comment.

File	Description
ClipboardCoreTests.cs	Added new tests covering custom formats, objects, file drops, images, metafiles, and text formats
System.Private.Windows.Core.Tests.csproj	Added references for drawing/GDI+ libraries and included bitmap content

Comments suppressed due to low confidence (1)

src/System.Private.Windows.Core/tests/System.Private.Windows.Core.Tests/System/Private/Windows/Ole/ClipboardCoreTests.cs:505

• The StringCollection is being initialized with a C# 12 array literal, which produces a string[], not a StringCollection. Use a collection initializer or add items via new StringCollection { "filePath", "filePath2" }.

        StringCollection filePaths =

[LeafShi1]

@JeremyKuhne Please help review this PR.

Currently all SimpleTests have been added to ClipboardCoreTests. Do the remaining cases need to be moved here?
Currently unimplemented, such as tests related to JsonDataObject and UntypedDataObject