Add code coverage for ListView.IconComparer

[MelonWang1]

Related #13442

Proposed changes

• Add unit test file: ListView.IconComparerTests.cs for public methods of the ListView.IconComparer.cs.cs

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull Request Overview

Adds a new unit test suite for ListView.IconComparer to validate its constructor, property setter, and comparison logic (including null handling).

• Introduces ListView.IconComparerTests.cs covering ascending/descending sort orders and null scenarios.
• Ensures Compare returns correct sign for item text comparisons.

Comments suppressed due to low confidence (1)

src/test/unit/System.Windows.Forms/System/Windows/Forms/ListView.IconComparerTests.cs:40

• Add an InlineData case for SortOrder.None in the Compare theory to ensure behavior under None is covered.

public void Compare_ComparesListViewItems_ByText_AndSortOrder(SortOrder order, string text1, string text2, int expectedSign)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.60627%. Comparing base (ee29cfd) to head (747305c).
Report is 36 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #13485         +/-   ##
===================================================
+ Coverage   76.59589%   76.60627%   +0.01037%     
===================================================
  Files           3230        3235          +5     
  Lines         639157      639321        +164     
  Branches       47295       47314         +19     
===================================================
+ Hits          489568      489760        +192     
+ Misses        146003      145987         -16     
+ Partials        3586        3574         -12     

Flag	Coverage Δ
Debug	76.60627% <100.00000%> (+0.01037%)	⬆️
integration	18.79192% <ø> (+0.00497%)	⬆️
production	51.02046% <ø> (+0.02150%)	⬆️
test	97.40051% <100.00000%> (-0.00361%)	⬇️
unit	48.41995% <ø> (+0.02009%)	⬆️

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[ricardobossan]

All LGTM!