void AssertFileWorkbookSaves(FilePath workbookPath, bool saveAs = false)
        {
            var workbookFileState = new WorkbookFile {
                Path = workbookPath.Name
            };

            workbookPath = GetTemporaryCopyOfWorkbook(workbookPath);

            var targetPath = saveAs ? workbookPath.ParentDirectory.Combine("NewWorkbook.workbook")
                : workbookPath;

            var workbookPackage = ReadWorkbookDocument(workbookPath);

            workbookPackage.Save(targetPath);
            AssertFileWorkbookUnchanged(targetPath, workbookFileState);
        }
 void AssertFileWorkbookUnchanged(FilePath workbookPath, WorkbookFile workbookFileState)
 {
     workbookPath.FileExists.ShouldBeTrue($"{workbookPath} no longer exists after saving.");
 }