Class tot test refactoring option to add test project

TestsCreatorCommands.cs

using System.Composition;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeRefactorings;
using Microsoft.CodeAnalysis.CSharp.Syntax;

namespace TestsCreatorCommandss
{
    [ExportCodeRefactoringProvider(RefactoringId, LanguageNames.CSharp)]
    [Shared]
    internal class TestsCreatorCommands : CodeRefactoringProvider
    {
        public const string RefactoringId = "CreateEmptyTest";

        public sealed override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
        {
            var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(continueOnCapturedContext: false);
            var node = root.FindNode(context.Span);

            var dec = node as MethodDeclarationSyntax;
            if (dec == null)
                return;

            context.RegisterRefactoring(CodeAction.Create("Create empty Test", c => CreateTest(context.Document, dec, c)));
        }

        private static async Task<Solution> CreateTest(Document document, MethodDeclarationSyntax method, CancellationToken cancellationToken)
        {
            var solution = document.Project.Solution;

            // Try to find existing test project
            var projectName = document.Project.Name + ".UnitTests";
            var testProject = solution.Projects.FirstOrDefault(x => x.Name == projectName);
            if (testProject == null)
            {
                // Create the project and update the solution
                testProject = solution.AddProject(projectName, projectName, LanguageNames.CSharp);
                solution = testProject.Solution;
            }

            solution.Workspace.CanApplyChange(ApplyChangesKind.AddProject)

            // Try to find existing test document
            var documentName = $"{((TypeDeclarationSyntax) method.Parent).Identifier.Text}Tests.cs";
            var testDocument = testProject.Documents.FirstOrDefault(x => x.Name == documentName);

            if (testDocument == null)
            {
                // Create the document and update the project and solution
                testDocument = testProject.AddDocument(documentName, "", document.Folders);
                testProject = testDocument.Project;
                solution = testProject.Solution;
            }

            return solution;
        }
    }
}