Tests | Expand UDT serialization code coverage

src/Microsoft.Data.SqlClient/tests/UnitTests/.editorconfig

@@ -0,0 +1,11 @@
+# editorconfig.org
+
+# top-most EditorConfig file
+root = false
+
+[*.cs]
+
+csharp_style_var_when_type_is_apparent = false:refactor
+# IDE0090: Use 'new(...)'
+csharp_style_implicit_object_creation_when_type_is_apparent = true:warning
+

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj

@@ -7,6 +7,7 @@
     <IntermediateOutputPath>$(ObjFolder)$(Configuration).$(Platform).$(AssemblyName)</IntermediateOutputPath>
     <OutputPath>$(BinFolder)$(Configuration).$(Platform).$(AssemblyName)</OutputPath>
     <IsTestProject>true</IsTestProject>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <!-- Common references -->
   <ItemGroup>
@@ -25,6 +26,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.DotNet.XUnitExtensions" />
+    <PackageReference Include="Microsoft.SqlServer.Server" />
   </ItemGroup>
   <!-- .NET Framework references -->
   <ItemGroup Condition="$(TargetGroup) == 'netfx'">

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/UdtSerialization/InvalidSerializationTest.cs

@@ -0,0 +1,62 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.IO;
+using Microsoft.Data.SqlClient.Server;
+using Microsoft.Data.SqlClient.UnitTests.UdtSerialization.SerializedTypes;
+using Microsoft.SqlServer.Server;
+using Xunit;
+
+namespace Microsoft.Data.SqlClient.UnitTests.UdtSerialization;
+
+/// <summary>
+/// Attempts to serialize types which do not meet the requirements for either user-defined or native serialization.
+/// </summary>
+public sealed class InvalidSerializationTest : IDisposable
+{
+    private readonly MemoryStream _stream;
+
+    /// <summary>
+    /// Initializes the MemoryStream used for all tests in this class.
+    /// </summary>
+    public InvalidSerializationTest()
+    {
+        _stream = new MemoryStream();
+    }
+
+    void IDisposable.Dispose()
+    {
+        _stream.Dispose();
+    }
+
+    /// <summary>
+    /// Attempts to serialize a class that does not have the SqlUserDefinedType attribute. Verifies that this fails.
+    /// </summary>
+    [Fact]
+    public void Serialize_MissingSqlUserDefinedTypeAttribute_Throws()
+    {
+        Action serialize = () => SerializationHelperSql9.Serialize(_stream, new ClassMissingSqlUserDefinedTypeAttribute());
+        var exception = Assert.Throws<InvalidUdtException>(serialize);
+
+        Assert.Equal($"'{typeof(ClassMissingSqlUserDefinedTypeAttribute).FullName}' is an invalid user defined type, reason: no UDT attribute.", exception.Message);
+    }
+
+    /// <summary>
+    /// Attempts to serialize a class that has a SqlUserDefinedType attribute, but specifies a Format enumeration value of
+    /// Unknown. Verifies that this fails.
+    /// </summary>
+    [Fact]
+    public void Serialize_UnknownFormattedType_Throws()
+    {
+        Action serialize = () => SerializationHelperSql9.Serialize(_stream, new UnknownFormattedClass());
+        var exception = Assert.Throws<ArgumentOutOfRangeException>("Format", serialize);
+
+#if NET
+        Assert.Equal("The Format enumeration value, 0, is not supported by the format method. (Parameter 'Format')", exception.Message);
+#else
+        Assert.Equal("The Format enumeration value, Unknown, is not supported by the format method.\r\nParameter name: Format", exception.Message);
+#endif
+    }
+}