private Document CreateProjectAndOpenNewDocument(Workspace workspace, ProjectInfo projectInfo, SourceText sourceText)
{
var documentId = DocumentId.CreateNewId(projectInfo.Id);
var solution = _workspace.CurrentSolution
.AddProject(projectInfo)
.AddDocument(documentId, "_", sourceText);
solution = _workspace.SetCurrentSolution(solution);
workspace.OpenDocument(documentId);
return(solution.GetDocument(documentId));
}