Add code coverage for ControlCodeDomSerializer (#13011)

Related #10773

Proposed changes
Add unit test file: ControlCodeDomSerializerTests.cs for public methods of the ControlCodeDomSerializer.cs.

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

@@ -0,0 +1,80 @@
+// 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.CodeDom;
+using System.ComponentModel;
+using System.ComponentModel.Design;
+using System.ComponentModel.Design.Serialization;
+using Moq;
+
+namespace System.Windows.Forms.Design.Tests;
+
+public class ControlCodeDomSerializerTests : IDisposable
+{
+    private readonly Mock<IDesignerSerializationManager> _managerMock;
+    private readonly Mock<IDesignerHost> _hostMock;
+    private readonly Mock<CodeDomSerializer> _serializerMock;
+    private readonly ControlCodeDomSerializer _controlCodeDomSerializer;
+    private readonly TestControl _testControl;
+    private readonly CodeStatementCollection _codeStatementCollection;
+
+    public ControlCodeDomSerializerTests()
+    {
+        _managerMock = new();
+        _hostMock = new();
+        _serializerMock = new();
+        _controlCodeDomSerializer = new();
+        _testControl = new();
+        _codeStatementCollection = [];
+
+        _managerMock.Setup(m => m.GetService(typeof(IDesignerHost))).Returns(_hostMock.Object);
+        _managerMock.Setup(m => m.GetSerializer(typeof(Component), typeof(CodeDomSerializer))).Returns(_serializerMock.Object);
+    }
+
+    public void Dispose() => _testControl.Dispose();
+
+    [Fact]
+    public void Deserialize_SuspendsAndResumesLayout()
+    {
+        Mock<IContainer> mockContainer = new();
+        _managerMock.Setup(m => m.GetService(typeof(IContainer))).Returns(mockContainer.Object);
+        mockContainer.Setup(c => c.Components).Returns(new ComponentCollection([_testControl]));
+
+        object codeObject = new();
+        object expectedObjectGraphData = new();
+        _serializerMock.Setup(s => s.Deserialize(_managerMock.Object, codeObject)).Returns(expectedObjectGraphData);
+
+        _controlCodeDomSerializer.Deserialize(_managerMock.Object, codeObject).Should().Be(expectedObjectGraphData);
+    }
+
+    [Fact]
+    public void Serialize_ShouldReturnSerializedObject()
+    {
+        _serializerMock.Setup(s => s.Serialize(_managerMock.Object, _testControl)).Returns(_codeStatementCollection);
+
+        CodeStatementCollection? result = _controlCodeDomSerializer.Serialize(_managerMock.Object, _testControl) as CodeStatementCollection;
+
+        result.Should().NotBeNull();
+        result.Should().BeOfType<CodeStatementCollection>();
+    }
+
+    public class TestControl : Control
+    {
+        public bool SuspendLayoutCalled { get; private set; }
+        public bool ResumeLayoutCalled { get; private set; }
+
+        public new void SuspendLayout()
+        {
+            SuspendLayoutCalled = true;
+            base.SuspendLayout();
+        }
+
+        public new void ResumeLayout(bool performLayout)
+        {
+            ResumeLayoutCalled = true;
+            base.ResumeLayout(performLayout);
+        }
+    }
+}