any way to add certificate authority for browser test?

[rch7]

Is there any way to add local certificate authority cert for browser test, or allow browser to read regular certificate store like ~/.pki/nssdb, or use persistent profile?
I know ignoreHTTPSErrors is on but it's not enough to test e.g. when third-party payment processors tries to load iframe as Chromium still shows "Not secure" in address bar and doesn't load all resources. HSTS may be an issue too.