Add unit test for PropertyGrid.PropertyTabCollection file (#13758)

Add more test for uncovered public methods in
PropertyGrid.PropertyTabCollectionTests.cs

Author: Olina-Zhang

src/test/unit/System.Windows.Forms/System/Windows/Forms/PropertyGrid.PropertyTabCollectionTests.cs

@@ -3,19 +3,34 @@
 
 #nullable disable
 
+using System.Collections;
 using System.ComponentModel;
 using System.Drawing;
 using System.Windows.Forms.Design;
 
 namespace System.Windows.Forms.Tests;
 
-public class PropertyTabCollectionTests
+public class PropertyTabCollectionTests : IDisposable
 {
+    private readonly PropertyGrid _propertyGrid;
+    private readonly PropertyGrid.PropertyTabCollection _propertyTabCollection;
+
+    public PropertyTabCollectionTests()
+    {
+        _propertyGrid = new PropertyGrid();
+        _propertyTabCollection = new PropertyGrid.PropertyTabCollection(_propertyGrid);
+    }
+
+    public void Dispose()
+    {
+        _propertyGrid.Dispose();
+    }
+
     [WinFormsTheory]
     [InlineData(typeof(PropertyGrid))]
     public void Count_ReturnsCorrectCount(Type ownerType)
     {
-        var owner = Activator.CreateInstance(ownerType) as PropertyGrid;
+        PropertyGrid owner = Activator.CreateInstance(ownerType) as PropertyGrid;
         TestPropertyTabCollection propertyTabCollection = new(owner);
         propertyTabCollection.Count.Should().Be(1); // PropertyGrid initially contains one PropertiesTab
     }
@@ -25,11 +40,11 @@ public void Count_ReturnsCorrectCount(Type ownerType)
     [InlineData(typeof(PropertyGrid), 1, typeof(TestPropertyTab))]
     public void Indexer_ReturnsCorrectTab(Type ownerType, int index, Type expectedTabType)
     {
-        var owner = Activator.CreateInstance(ownerType) as PropertyGrid;
+        PropertyGrid owner = Activator.CreateInstance(ownerType) as PropertyGrid;
         TestPropertyTabCollection propertyTabCollection = new(owner);
         propertyTabCollection.AddTabType(typeof(TestPropertyTab));
 
-        var tab = propertyTabCollection[index];
+        PropertyTab tab = propertyTabCollection[index];
         tab.Should().BeOfType(expectedTabType);
     }
 
@@ -38,7 +53,7 @@ public void Indexer_ReturnsCorrectTab(Type ownerType, int index, Type expectedTa
     [InlineData(typeof(PropertyGrid), typeof(TestPropertyTab), 2, true)]
     public void AddTabType_WithDifferentInputs(Type ownerType, Type tabType, int expectedCount, bool addTwice)
     {
-        var owner = Activator.CreateInstance(ownerType) as PropertyGrid;
+        PropertyGrid owner = Activator.CreateInstance(ownerType) as PropertyGrid;
         TestPropertyTabCollection propertyTabCollection = new(owner);
         int initialCount = propertyTabCollection.Count;
 
@@ -55,6 +70,92 @@ public void AddTabType_WithDifferentInputs(Type ownerType, Type tabType, int exp
         }
     }
 
+    [WinFormsFact]
+    public void AddTabType_AddsTab()
+    {
+        int initialCount = _propertyTabCollection.Count;
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab));
+
+        _propertyTabCollection.Count.Should().Be(initialCount + 1);
+        _propertyTabCollection[initialCount].Should().BeOfType<TestPropertyTab>();
+    }
+
+    [WinFormsFact]
+    public void AddTabType_WithScope_AddsTab()
+    {
+        int initialCount = _propertyTabCollection.Count;
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab), PropertyTabScope.Component);
+
+        _propertyTabCollection.Count.Should().Be(initialCount + 1);
+        _propertyTabCollection[initialCount].Should().BeOfType<TestPropertyTab>();
+    }
+
+    [WinFormsFact]
+    public void RemoveTabType_RemovesTab()
+    {
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab));
+        int countAfterAdd = _propertyTabCollection.Count;
+
+        _propertyTabCollection.RemoveTabType(typeof(TestPropertyTab));
+
+        _propertyTabCollection.Count.Should().Be(countAfterAdd - 1);
+        _propertyTabCollection.Cast<PropertyTab>().Should().NotContain(tab => tab is TestPropertyTab);
+    }
+
+    [WinFormsFact]
+    public void Clear_RemovesTabsOfGivenScope()
+    {
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab), PropertyTabScope.Component);
+        int countAfterAdd = _propertyTabCollection.Count;
+
+        _propertyTabCollection.Clear(PropertyTabScope.Component);
+
+        _propertyTabCollection.Count.Should().BeLessThan(countAfterAdd);
+    }
+
+    [WinFormsFact]
+    public void CopyTo_CopiesTabsToArray()
+    {
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab));
+        PropertyTab[] array = new PropertyTab[_propertyTabCollection.Count];
+
+        ((ICollection)_propertyTabCollection).CopyTo(array, 0);
+
+        array.Should().ContainItemsAssignableTo<PropertyTab>();
+        array.Should().Contain(tab => tab is TestPropertyTab);
+    }
+
+    [WinFormsFact]
+    public void GetEnumerator_EnumeratesTabs()
+    {
+        _propertyTabCollection.AddTabType(typeof(TestPropertyTab));
+
+        int count = 0;
+        foreach (PropertyTab tab in _propertyTabCollection)
+        {
+            tab.Should().NotBeNull();
+            count++;
+        }
+
+        count.Should().Be(_propertyTabCollection.Count);
+    }
+
+    [WinFormsFact]
+    public void SyncRoot_ReturnsSelf()
+    {
+        object syncRoot = ((ICollection)_propertyTabCollection).SyncRoot;
+
+        syncRoot.Should().BeSameAs(_propertyTabCollection);
+    }
+
+    [WinFormsFact]
+    public void IsSynchronized_ReturnsFalse()
+    {
+        bool isSynchronized = ((ICollection)_propertyTabCollection).IsSynchronized;
+
+        isSynchronized.Should().BeFalse();
+    }
+
     public class TestPropertyTabCollection : PropertyGrid.PropertyTabCollection
     {
         public TestPropertyTabCollection(PropertyGrid ownerPropertyGrid) : base(ownerPropertyGrid)
@@ -72,18 +173,7 @@ public class TestPropertyTab : PropertyTab, IDisposable
 
         public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object component, Attribute[] attributes) => TypeDescriptor.GetProperties(component, attributes);
 
-        public override Bitmap Bitmap
-        {
-            get
-            {
-                if (_bitmap is null)
-                {
-                    _bitmap = new Bitmap(1, 1);
-                }
-
-                return _bitmap;
-            }
-        }
+        public override Bitmap Bitmap => _bitmap ??= new(1, 1);
 
         public override void Dispose()
         {