From 7d887519300b04881d228ca5fa5ee3ffcecca570 Mon Sep 17 00:00:00 2001
From: v-zhgl <38325459+Zheng-Li01@users.noreply.github.com>
Date: Wed, 18 Dec 2024 19:06:48 +0000
Subject: [PATCH] Add code coverage for DataGridViewCellConverter (#12622)

related #10453

Add unit tests for DataGridViewCellConverter.cs to test its methods
---
 .../Forms/DataGridViewCellConverterTests.cs   | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/DataGridViewCellConverterTests.cs

diff --git a/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/DataGridViewCellConverterTests.cs b/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/DataGridViewCellConverterTests.cs
new file mode 100644
index 00000000000..2e46cb78ba2
--- /dev/null
+++ b/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/DataGridViewCellConverterTests.cs
@@ -0,0 +1,52 @@
+// 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.Design.Serialization;
+using System.Globalization;
+
+namespace System.Windows.Forms.Tests;
+
+public class DataGridViewCellConverterTests
+{
+    private readonly DataGridViewCellConverter _converter = new();
+
+    [WinFormsTheory]
+    [InlineData(typeof(InstanceDescriptor), true)]
+    [InlineData(typeof(string), true)]
+    public void CanConvertTo_ReturnsExpected(Type destinationType, bool expected) =>
+        _converter.CanConvertTo(context: null, destinationType).Should().Be(expected);
+
+    [WinFormsFact]
+    public void ConvertTo_InstanceDescriptorWithDataGridViewCell_ReturnsInstanceDescriptor()
+    {
+        using DataGridViewTextBoxCell cell = new();
+        Type destinationType = typeof(InstanceDescriptor);
+
+        _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, cell, destinationType).Should().NotBeNull();
+        _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, cell, destinationType).Should().BeOfType<InstanceDescriptor>();
+    }
+
+    [WinFormsFact]
+    public void ConvertTo_InstanceDescriptorWithNonDataGridViewCell_ThrowsNotSupportedException()
+    {
+        object value = new();
+        Type destinationType = typeof(InstanceDescriptor);
+
+        Action action = () => _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, value, destinationType);
+        action.Should().Throw<NotSupportedException>()
+            .WithMessage("'DataGridViewCellConverter' is unable to convert 'System.Object' to 'System.ComponentModel.Design.Serialization.InstanceDescriptor'.");
+    }
+
+    [WinFormsFact]
+    public void ConvertTo_OtherType_ReturnsStringRepresentation()
+    {
+        using DataGridViewTextBoxCell cell = new();
+        Type destinationType = typeof(string);
+
+        _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, cell, destinationType).Should().NotBeNull();
+        _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, cell, destinationType).Should().BeOfType<string>();
+        _converter.ConvertTo(context: null, CultureInfo.InvariantCulture, cell, destinationType).Should().Be(cell.ToString());
+    }
+}