Jenny has a debug mode, where you can inspect requests, save and replay them, but more impressively it can generate tests from saved requests.
To start with debug mode just type
jenny serve github.com/Typeform/users/cmd/users
debug mode requires that the package you want to serve is a
main package, it
-addr flag to pass in which port the app should listen to, and that's
var ( addr = flag.String("addr", ":8080", "-addr :8080") )