Content Security Policy, X-Frame-Options, and localhost

Kind of a 101 question about X-Frame-Options and/or Content-Security-Policy: frame-ancestors: if one intends to develop an application using iframed production sites (on which I can adjust headers) on a local machine, would they have to add localhost to frame-ancestors in the Content-Security-Policy? Will X-Frame-Options SAMEORIGIN not work at all?