Add unit tests for DesignerFrame

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

@@ -0,0 +1,128 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#nullable enable
+
+using System.ComponentModel;
+using System.Drawing;
+using Moq;
+
+namespace System.Windows.Forms.Design.Tests;
+
+public class DesignerFrameTests : IDisposable
+{
+    private readonly Mock<ISite> _mockSite = new();
+    private DesignerFrame _designerFrame;
+
+    public DesignerFrameTests() => _designerFrame = new(_mockSite.Object);
+
+    public void Dispose() => _designerFrame.Dispose();
+
+    private void SetupMocks()
+    {
+        Mock<IUIService> mockUIService = new();
+        mockUIService.Setup(ui => ui.Styles["ArtboardBackground"]).Returns(Color.Red);
+        _mockSite.Setup(site => site.GetService(typeof(IUIService))).Returns(mockUIService.Object);
+    }
+
+    [Fact]
+    public void DesignerFrame_Constructor_SetsProperties()
+    {
+        SetupMocks();
+
+        using (_designerFrame = new DesignerFrame(_mockSite.Object))
+        {
+            _designerFrame.Text.Should().Be("DesignerFrame");
+            _designerFrame.BackColor.Should().Be(Color.Red);
+
+            _designerFrame.Controls.Cast<Control>().Should().HaveCount(1);
+        }
+    }
+
+    [Fact]
+    public void DesignerFrame_Initialize_SetsDesignerProperties()
+    {
+        Control control = new();
+        try
+        {
+            _designerFrame.Initialize(control);
+
+            List<Control> controls = _designerFrame.Controls.Cast<Control>().ToList();
+            Control? designerRegion = controls.FirstOrDefault(c => c is ScrollableControl);
+
+            designerRegion.Should().NotBeNull();
+
+            Control? designer = designerRegion?.Controls.Cast<Control>().FirstOrDefault();
+            designer.Should().Be(control);
+
+            control.Visible.Should().BeTrue();
+            control.Enabled.Should().BeTrue();
+
+            _designerFrame.Controls.Cast<Control>().Should().NotContain(control);
+        }
+        finally
+        {
+            control.Dispose();
+        }
+    }
+
+    [Fact]
+    public void DesignerFrame_ProcessDialogKey_ReturnsExpectedResult()
+    {
+        using (_designerFrame = new DesignerFrame(_mockSite.Object))
+        {
+            bool result = _designerFrame.TestAccessor().Dynamic.ProcessDialogKey(Keys.Enter);
+
+            result.Should().BeFalse();
+        }
+    }
+
+    [Fact]
+    public void DesignerFrame_Constructor_SetsSiteProperty()
+    {
+        _designerFrame.Site ??= _mockSite.Object;
+
+        _designerFrame.Should().NotBeNull();
+        _designerFrame.Site.Should().Be(_mockSite.Object);
+    }
+
+    [Fact]
+    public void DesignerFrame_AddControl_AddsControlToFrame()
+    {
+        Control control = new();
+        try
+        {
+            _designerFrame.Controls.Add(control);
+
+            _designerFrame.Controls.Cast<Control>().Should().Contain(control);
+        }
+        finally
+        {
+            control.Dispose();
+        }
+    }
+
+    [Fact]
+    public void DesignerFrame_Resize_TriggersExpectedBehavior()
+    {
+        using (_designerFrame = new DesignerFrame(_mockSite.Object))
+        {
+            _designerFrame.Resize += (sender, args) => { /* Handle resize if needed */ };
+
+            _designerFrame.Width = 500;
+
+            _designerFrame.Width.Should().Be(500);
+        }
+    }
+
+    [Fact]
+    public void Designer_ProcessDialogKey()
+    {
+        using (_designerFrame = new DesignerFrame(_mockSite.Object))
+        {
+            bool result = _designerFrame.TestAccessor().Dynamic.ProcessDialogKey(Keys.Enter);
+
+            result.Should().BeFalse();
+        }
+    }
+}