Add unit tests for ParentControlDesigner (#13173)

Related #10773

Proposed changes
Add unit test ParentControlDesignerTests.cs for public properties and method of the ParentControlDesigner.

Author: MelonWang1

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

@@ -0,0 +1,234 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.ComponentModel;
+using System.ComponentModel.Design;
+using System.Drawing;
+using System.Drawing.Design;
+using System.Reflection;
+using System.Windows.Forms.Design.Behavior;
+using Moq;
+
+namespace System.Windows.Forms.Design.Tests;
+public class ParentControlDesignerTests : IDisposable
+{
+    private readonly ParentControlDesigner _designer;
+    private readonly Control _control;
+
+    public ParentControlDesignerTests()
+    {
+        _designer = new();
+        _control = new();
+        _designer.Initialize(_control);
+    }
+
+    public void Dispose()
+    {
+        _control.Dispose();
+        _designer.Dispose();
+    }
+
+    [Fact]
+    public void SnapLines_ReturnsExpectedSnapLines()
+    {
+        IList<SnapLine> snapLines = _designer.SnapLines.Cast<SnapLine>().ToList();
+
+        snapLines.Should().NotBeNull();
+        snapLines.Should().BeOfType<List<SnapLine>>();
+        ((List<SnapLine>)snapLines).Should().NotBeEmpty();
+        ((List<SnapLine>)snapLines).Should().OnlyHaveUniqueItems();
+
+        ((List<SnapLine>)snapLines).Should()
+            .Contain(sl => sl.SnapLineType == SnapLineType.Top)
+            .And.Contain(sl => sl.SnapLineType == SnapLineType.Bottom)
+            .And.Contain(sl => sl.SnapLineType == SnapLineType.Left)
+            .And.Contain(sl => sl.SnapLineType == SnapLineType.Right);
+    }
+
+    [Fact]
+    public void CanParent_ControlDesigner_ReturnsExpected()
+    {
+        Mock<ControlDesigner> mockControlDesigner = new();
+        Mock<Control> mockControl = new();
+        mockControlDesigner.Setup(cd => cd.Control).Returns(mockControl.Object);
+
+        _designer.CanParent(mockControlDesigner.Object).Should().BeTrue();
+    }
+
+    [Fact]
+    public void CanParent_Control_ReturnsExpected()
+    {
+        using TestControl testControl = new() { ContainsControl = false };
+
+        _designer.CanParent(testControl).Should().BeTrue();
+    }
+
+    [Fact]
+    public void GetGlyphs_SelectionTypeSelected_AddsContainerSelectorGlyph()
+    {
+        Mock<IServiceProvider> mockServiceProvider = new();
+        Mock<ISite> mockSite = new();
+        Mock<IDesignerHost> mockDesignerHost = new();
+        Mock<IComponentChangeService> mockChangeService = new();
+        _control.Site = mockSite.Object;
+        mockSite.Setup(s => s.GetService(typeof(IDesignerHost))).Returns(mockDesignerHost.Object);
+        mockSite.Setup(s => s.GetService(typeof(IComponentChangeService))).Returns(mockChangeService.Object);
+
+        Mock<DesignerFrame> mockDesignerFrame = new(mockSite.Object) { CallBase = true };
+        BehaviorService behaviorService = new(mockServiceProvider.Object, mockDesignerFrame.Object);
+        mockServiceProvider.Setup(sp => sp.GetService(typeof(BehaviorService))).Returns(() => behaviorService);
+        mockSite.Setup(s => s.GetService(typeof(BehaviorService))).Returns(behaviorService);
+
+        _designer.TestAccessor().Dynamic._behaviorService = behaviorService;
+        _designer.TestAccessor().Dynamic._host = mockDesignerHost.Object;
+        _designer.TestAccessor().Dynamic._changeService = mockChangeService.Object;
+
+        GlyphSelectionType selectionType = GlyphSelectionType.Selected;
+
+        GlyphCollection glyphs = _designer.GetGlyphs(selectionType);
+
+        glyphs.Should().BeOfType<GlyphCollection>();
+        glyphs.OfType<ContainerSelectorGlyph>().Count().Should().Be(1);
+    }
+
+    [Fact]
+    public void InitializeNewComponent_WithNullDefaultValues_DoesNotThrow()
+    {
+        _designer.Invoking(d => d.InitializeNewComponent(null)).Should().NotThrow();
+    }
+
+    [WinFormsFact]
+    public void InitializeNewComponent_ShouldReparentControls_WhenAllowControlLassoIsTrue()
+    {
+        Mock<IDesignerHost> mockDesignerHost = new();
+        Mock<ISite> mockSite = new();
+        Mock<ISelectionService> mockSelectionService = new();
+        Mock<IComponentChangeService> mockChangeService = new();
+
+        using TestControl testComponent = new();
+        using TestControl parentComponent = new();
+
+        mockSite.Setup(s => s.GetService(typeof(IDesignerHost))).Returns(mockDesignerHost.Object);
+        mockSite.Setup(s => s.GetService(typeof(ISelectionService))).Returns(mockSelectionService.Object);
+        mockSite.Setup(s => s.GetService(typeof(IComponentChangeService))).Returns(mockChangeService.Object);
+        testComponent.Site = mockSite.Object;
+        parentComponent.Site = mockSite.Object;
+
+        mockDesignerHost.Setup(h => h.GetDesigner(parentComponent)).Returns(_designer);
+
+        _designer.Initialize(testComponent);
+        _designer.TestAccessor().Dynamic._changeService = mockChangeService.Object;
+
+        Dictionary<string, object> defaultValues = new()
+        {
+            { "Size", new Size(100, 100) },
+            { "Location", new Point(10, 10) },
+            { "Parent", parentComponent }
+        };
+
+        DisableDragDrop(testComponent);
+        DisableDragDrop(parentComponent);
+
+        _designer.InitializeNewComponent(defaultValues);
+
+        mockDesignerHost.Verify(h => h.GetDesigner(parentComponent), Times.AtMost(2));
+    }
+
+    public class TestControl : Control
+    {
+        public bool ContainsControl { get; set; }
+
+        public new bool Contains(Control ctl)
+        {
+            return ContainsControl;
+        }
+
+        public new ControlCollection Controls => base.Controls;
+    }
+
+    private void DisableDragDrop(Control control)
+    {
+        if (control is null)
+            return;
+
+        control.AllowDrop = false;
+        foreach (Control child in control.Controls)
+        {
+            DisableDragDrop(child);
+        }
+    }
+
+    [Fact]
+    public void AllowSetChildIndexOnDrop_ReturnsTrue()
+    {
+        _designer.AllowSetChildIndexOnDrop.Should().BeTrue();
+    }
+
+    [Fact]
+    public void CanAddComponent_ReturnsTrue()
+    {
+        Mock<IComponent> mockComponent = new();
+        _designer.CanAddComponent(mockComponent.Object).Should().BeTrue();
+    }
+
+    [Fact]
+    public void EnableDragRect_ReturnsTrue()
+    {
+        bool enableDragRect = _designer.TestAccessor().Dynamic.EnableDragRect;
+        enableDragRect.Should().BeTrue();
+    }
+
+    [Fact]
+    public void GridSize_DefaultValue_ReturnsExpected()
+    {
+        Size gridSize = _designer.TestAccessor().Dynamic.GridSize;
+        gridSize.Should().Be(new Size(8, 8));
+    }
+
+    [Fact]
+    public void GridSize_SetValue_UpdatesGridSize()
+    {
+        Size newSize = new Size(10, 10);
+        _designer.TestAccessor().Dynamic.GridSize = newSize;
+        Size gridSize = _designer.TestAccessor().Dynamic.GridSize;
+        gridSize.Should().Be(newSize);
+    }
+
+    [Fact]
+    public void GridSize_SetValue_InvalidSize_ThrowsArgumentException()
+    {
+        Action action = () => _designer.TestAccessor().Dynamic.GridSize = new Size(1, 1);
+        action.Should().Throw<TargetInvocationException>()
+            .WithInnerException<ArgumentException>()
+            .WithMessage("*'GridSize'*");
+
+        action = () => _designer.TestAccessor().Dynamic.GridSize = new Size(201, 201);
+        action.Should().Throw<TargetInvocationException>()
+            .WithInnerException<ArgumentException>()
+            .WithMessage("*'GridSize'*");
+    }
+
+    [Fact]
+    public void MouseDragTool_DefaultValue_ReturnsNull()
+    {
+        ToolboxItem mouseDragTool = _designer.TestAccessor().Dynamic.MouseDragTool;
+        mouseDragTool.Should().BeNull();
+    }
+
+    [Fact]
+    public void MouseDragTool_SetValue_ReturnsExpected()
+    {
+        ToolboxItem toolboxItem = new(typeof(Button));
+        _designer.TestAccessor().Dynamic._mouseDragTool = toolboxItem;
+        ToolboxItem mouseDragTool = _designer.TestAccessor().Dynamic.MouseDragTool;
+        mouseDragTool.Should().Be(toolboxItem);
+    }
+
+    [Fact]
+    public void GetParentForComponent_ReturnsControl()
+    {
+        Mock<IComponent> mockComponent = new();
+        Control parentControl = _designer.TestAccessor().Dynamic.GetParentForComponent(mockComponent.Object);
+        parentControl.Should().Be(_control);
+    }
+}