Add code coverage for DesignerUtils

src/System.Windows.Forms.Design/tests/UnitTests/System/Windows/Forms/Design/DesignerUtilsTests.cs

@@ -1,7 +1,10 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections;
+using System.ComponentModel;
 using System.ComponentModel.Design;
+using System.ComponentModel.Design.Serialization;
 using System.Drawing;
 using System.Drawing.Imaging;
 using System.Windows.Forms.Design.Behavior;
@@ -400,4 +403,183 @@ internal void GetBoundsForSelectionType_ShouldReturnExpectedBounds(
         result.Width.Should().Be(expectedWidth);
         result.Height.Should().Be(expectedHeight);
     }
+
+    [WinFormsFact]
+    public void ApplyListViewThemeStyles_ShouldSetWindowThemeToExplorer()
+    {
+        using ListView listView = new();
+        Exception? exception = Record.Exception(() => DesignerUtils.ApplyListViewThemeStyles(listView));
+        exception.Should().BeNull();
+        listView.IsHandleCreated.Should().BeTrue();
+    }
+
+    [WinFormsFact]
+    public void ApplyListViewThemeStyles_ShouldThrowArgumentNullException_WhenListViewIsNull()
+    {
+        Action action = () => DesignerUtils.ApplyListViewThemeStyles(null!);
+        action.Should().Throw<ArgumentNullException>();
+    }
+
+    [WinFormsFact]
+    public void ApplyTreeViewThemeStyles_ShouldSetWindowThemeToExplorer()
+    {
+        using TreeView treeView = new();
+        Exception? exception = Record.Exception(() => DesignerUtils.ApplyTreeViewThemeStyles(treeView));
+        exception.Should().BeNull();
+        treeView.IsHandleCreated.Should().BeTrue();
+    }
+
+    [WinFormsFact]
+    public void ApplyTreeViewThemeStyles_ShouldThrowArgumentNullException_WhenTreeViewIsNull()
+    {
+        Action action = () => DesignerUtils.ApplyTreeViewThemeStyles(null!);
+        action.Should().Throw<ArgumentNullException>();
+    }
+
+    [WinFormsFact]
+    public void CheckForNestedContainer_ShouldReturnSameContainer_WhenNotNested()
+    {
+        Mock<IContainer> nestedContainer = new();
+        IContainer? result = DesignerUtils.CheckForNestedContainer(nestedContainer.Object);
+        result.Should().BeSameAs(nestedContainer.Object);
+    }
+
+    [WinFormsFact]
+    public void FilterGenericTypes_ShouldReturnNull_WhenTypesIsNull()
+    {
+        ICollection? result = DesignerUtils.FilterGenericTypes(null);
+        result.Should().BeNull();
+    }
+
+    [WinFormsFact]
+    public void FilterGenericTypes_ShouldReturnEmptyCollection_WhenTypesIsEmpty()
+    {
+        ICollection emptyCollection = Array.Empty<Type>();
+        ICollection? result = DesignerUtils.FilterGenericTypes(emptyCollection);
+        result.Should().BeSameAs(emptyCollection);
+    }
+
+    [WinFormsFact]
+    public void FilterGenericTypes_ShouldFilterOutGenericTypes()
+    {
+        ICollection types = new List<Type>
+        {
+            typeof(List<>),
+            typeof(int),
+            typeof(Dictionary<,>),
+            typeof(string)
+        };
+
+        ICollection? result = DesignerUtils.FilterGenericTypes(types);
+
+        result.Should().NotBeNull();
+        result.Should().BeOfType<List<Type>>();
+        result.Should().BeEquivalentTo(new List<Type> { typeof(int), typeof(string) });
+    }
+
+    [WinFormsFact]
+    public void GetUniqueSiteName_ShouldReturnNull_WhenNameIsNullOrEmpty()
+    {
+        Mock<IDesignerHost> mockHost = new();
+        string? result = DesignerUtils.GetUniqueSiteName(mockHost.Object, null);
+        result.Should().BeNull();
+
+        result = DesignerUtils.GetUniqueSiteName(mockHost.Object, string.Empty);
+        result.Should().BeNull();
+    }
+
+    [WinFormsFact]
+    public void GetUniqueSiteName_ShouldReturnName_WhenNameIsNotInUseAndValid()
+    {
+        Mock<IDesignerHost> mockHost = new();
+        Mock<INameCreationService> mockNameCreationService = new();
+        mockNameCreationService.Setup(s => s.IsValidName("TestName")).Returns(true);
+
+        mockHost.Setup(h => h.GetService(typeof(INameCreationService))).Returns(mockNameCreationService.Object);
+
+        ComponentCollection components = new(Array.Empty<IComponent>());
+        Mock<IContainer> mockContainer = new();
+        mockContainer.Setup(c => c.Components).Returns(components);
+        mockHost.Setup(h => h.Container).Returns(mockContainer.Object);
+
+        string? result = DesignerUtils.GetUniqueSiteName(mockHost.Object, "TestName");
+
+        result.Should().Be("TestName");
+    }
+
+    [WinFormsTheory]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Top, false, 0, 10)]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Bottom, false, 0, -90)]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Left, false, 10, 0)]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Right, false, -90, 0)]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Top, true, 0, 10)]
+    [InlineData(0, 0, 100, 100, 10, 10, ToolboxSnapDragDropEventArgs.SnapDirection.Right, true, -10, 0)]
+    internal void GetBoundsFromToolboxSnapDragDropInfo_ShouldReturnExpectedBounds(
+        int x,
+        int y,
+        int width,
+        int height,
+        int offsetX,
+        int offsetY,
+        ToolboxSnapDragDropEventArgs.SnapDirection snapDirection,
+        bool isMirrored,
+        int expectedX,
+        int expectedY)
+    {
+        Rectangle originalBounds = new(x, y, width, height);
+        ToolboxSnapDragDropEventArgs args = new(
+         snapDirection,
+         new Point(offsetX, offsetY),
+         new DragEventArgs(
+             null,
+             0,
+             0,
+             0,
+             DragDropEffects.None,
+             DragDropEffects.None));
+
+        Rectangle result = DesignerUtils.GetBoundsFromToolboxSnapDragDropInfo(
+            e: args,
+            originalBounds: originalBounds,
+            isMirrored: isMirrored);
+
+        result.X.Should().Be(expectedX);
+        result.Y.Should().Be(expectedY);
+    }
+
+    [WinFormsTheory]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.TopLeft, 14)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.TopCenter, 14)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.TopRight, 14)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.MiddleLeft, 31)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.MiddleCenter, 31)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.MiddleRight, 31)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.BottomLeft, 48)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.BottomCenter, 48)]
+    [InlineData(100, 50, "Arial", 10, ContentAlignment.BottomRight, 48)]
+    [InlineData(200, 100, "Times New Roman", 12, ContentAlignment.TopLeft, 16)]
+    [InlineData(200, 100, "Times New Roman", 12, ContentAlignment.MiddleCenter, 57)]
+    [InlineData(200, 100, "Times New Roman", 12, ContentAlignment.BottomRight, 97)]
+    public void GetTextBaseline_ShouldReturnExpectedBaseline_WithVariousFontsAndBounds(
+        int width, int height, string fontFamily, float fontSize, ContentAlignment alignment, int expectedBaseline)
+    {
+        using Button button = new()
+        {
+            Width = width,
+            Height = height,
+            Font = new Font(fontFamily, fontSize)
+        };
+
+        int baseline = DesignerUtils.GetTextBaseline(button, alignment);
+
+        baseline.Should().Be(expectedBaseline);
+    }
+
+    [WinFormsFact]
+    public void GetTextBaseline_ShouldThrowNullException_WhenControlIsNull()
+    {
+        Action action = () => DesignerUtils.GetTextBaseline(null!, ContentAlignment.TopLeft);
+
+        action.Should().Throw<NullReferenceException>();
+    }
 }