Add code coverage for DataGridViewComboBoxCell.ObjectCollection

[Zheng-Li01]

related #10453

Proposed changes

Add unit tests for DataGridViewComboBoxCell.ObjectCollection.cs to test its properties & methods

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.92431%. Comparing base (f432c76) to head (0e283df).
Report is 22 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12580         +/-   ##
===================================================
+ Coverage   75.83381%   75.92431%   +0.09050%     
===================================================
  Files           3164        3167          +3     
  Lines         636443      636883        +440     
  Branches       47002       47011          +9     
===================================================
+ Hits          482639      483549        +910     
+ Misses        150347      149869        -478     
- Partials        3457        3465          +8     

Flag	Coverage Δ
Debug	75.92431% <100.00000%> (+0.09050%)	⬆️
integration	18.17244% <ø> (-0.00813%)	⬇️
production	49.62409% <ø> (+0.17023%)	⬆️
test	97.05239% <100.00000%> (-0.00002%)	⬇️
unit	46.84137% <ø> (+0.19807%)	⬆️

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[ricardobossan]

All LGTM!

[ricardobossan]

Hi @Tanya-Solyanik

While reviewing the test code for the DataGridViewComboBoxCell.ObjectCollection class, I encountered a System.InvalidCastException in the AddRange(ObjectCollection value) method. Specifically, the following line:

AddRangeInternal((ICollection<object>)value);

Here's the stack trace:

System.InvalidCastException: Unable to cast object of type 'ObjectCollection' to type 'System.Collections.Generic.ICollection`1[System.Object]'.
   at DataGridViewComboBoxCell.ObjectCollection.AddRange(ObjectCollection value)

This indicates a casting issue when passing ObjectCollection to AddRangeInternal. After testing, I found a working solution by modifying the AddRange and AddRangeInternal methods as follows:

public void AddRange(ObjectCollection value)
{
    _owner.CheckNoDataSource();
    AddRangeInternal(value);
    _owner.OnItemsCollectionChanged();
}

internal void AddRangeInternal(ObjectCollection items)
{
    ArgumentNullException.ThrowIfNull(items);

    foreach (object item in items)
    {
        if (item is null)
        {
            throw new InvalidOperationException(SR.InvalidNullItemInCollection);
        }
    }

    InnerArray.Add(items);
    if (_owner.Sorted)
    {
        InnerArray.Sort(Comparer);
    }
}

This implementation avoids the invalid cast and ensures the method functions as expected. Please let me know your thoughts.

[Tanya-Solyanik]

Added some minor suggestions

[Tanya-Solyanik]

@ricardobossan - please create a new issue and submit a PR, great find!