public bool CanFindToolwindow(Guid persistenceGuid)
{
IVsUIShell uiShellService = VsIdeTestHostContext.ServiceProvider.GetService(typeof(SVsUIShell)) as IVsUIShell;
Assert.IsNotNull(uiShellService);
IVsWindowFrame windowFrame;
int hr = uiShellService.FindToolWindow((uint)__VSFINDTOOLWIN.FTW_fFindFirst, ref persistenceGuid, out windowFrame);
Assert.IsTrue(hr == VSConstants.S_OK);
return (windowFrame != null);
}