Semantic snippets tests (#74808)

* Add infrustructure for semantic snippet testing

* Port `foreach` snippet

* Port `for` snippet

* Port `forr` snippet

* Port `lock` snippet

* Port `else` snippet

* Port `cw` snippet

* Port `ctor` snippet

* Port `svm` and `sim` snippets

* Port `class` snippet

* Port `struct` snippet

* Port `interface` snippet

* Port `enum` snippet

* Port `do` snippet

* Port `if` and `while` snippets

* Port `prop`, `propg` and `propi` snippets and remove leftover legacy snippet test infrastructure

* Do not show `enum` snippet after `partial` modifier

* Use common test data in a few more places

* Fix build

* Fix

src/CodeStyle/Core/Tests/UnitTestUtilities/Microsoft.CodeAnalysis.CodeStyle.UnitTestUtilities.csproj

@@ -24,7 +24,7 @@
     <Compile Include="..\..\..\..\Features\DiagnosticsTestUtilities\CodeActions\VisualBasicCodeRefactoringVerifier`1.cs" Link="VisualBasicCodeRefactoringVerifier`1.cs" />
     <Compile Include="..\..\..\..\Features\DiagnosticsTestUtilities\Diagnostics\ParenthesesOptionsProvider.cs" Link="ParenthesesOptionsProvider.cs" />
     <Compile Include="..\..\..\..\Features\DiagnosticsTestUtilities\NamingStyles\NamingStylesTestOptionSets.cs" Link="NamingStyles\NamingStylesTestOptionSets.cs" />
-    <Compile Include="..\..\..\..\Features\DiagnosticsTestUtilities\Utilities\StringSyntaxAttribute.cs" Link="Utilities\StringSyntaxAttribute.cs" />
+    <Compile Include="..\..\..\..\Features\TestUtilities\Utilities\StringSyntaxAttribute.cs" Link="Utilities\StringSyntaxAttribute.cs" />
     <Compile Include="..\..\..\..\Workspaces\CoreTestUtilities\OptionsCollection.cs" Link="OptionsCollection.cs" />
   </ItemGroup>
   <ItemGroup Label="Project References">

src/EditorFeatures/CSharpTest/Completion/CompletionProviders/SemanticSnippetCompletionProviderTests.cs

@@ -0,0 +1,81 @@
+// 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.Threading.Tasks;
+using Microsoft.CodeAnalysis.CSharp.Completion.CompletionProviders.Snippets;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Roslyn.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Completion.CompletionProviders;
+
+[Trait(Traits.Feature, Traits.Features.Completion)]
+public sealed class SemanticSnippetCompletionProviderTests : AbstractCSharpCompletionProviderTests
+{
+    public SemanticSnippetCompletionProviderTests()
+    {
+        ShowNewSnippetExperience = true;
+    }
+
+    internal override Type GetCompletionProviderType()
+        => typeof(CSharpSnippetCompletionProvider);
+
+    [WpfFact]
+    public async Task InsertConsoleSnippetWithInvocationBeforeAndAfterCursorTest()
+    {
+        var markupBeforeCommit = """
+            class Program
+            {
+                public void Method()
+                {
+                    Wr$$Blah
+                }
+            }
+            """;
+
+        var expectedCodeAfterCommit = """
+            using System;
+
+            class Program
+            {
+                public void Method()
+                {
+                    Console.WriteLine($$);
+                }
+            }
+            """;
+
+        await VerifyCustomCommitProviderAsync(markupBeforeCommit, "cw", expectedCodeAfterCommit);
+    }
+
+    [WpfFact]
+    public async Task InsertConsoleSnippetWithInvocationUnderscoreBeforeAndAfterCursorTest()
+    {
+        var markupBeforeCommit =
+            """
+            class Program
+            {
+                public void Method()
+                {
+                    _Wr$$Blah_
+                }
+            }
+            """;
+
+        var expectedCodeAfterCommit =
+            """
+            using System;
+
+            class Program
+            {
+                public void Method()
+                {
+                    Console.WriteLine($$);
+                }
+            }
+            """;
+        await VerifyCustomCommitProviderAsync(markupBeforeCommit, "cw", expectedCodeAfterCommit);
+    }
+}