main.go test error

[elyock]

I'm still learning Go, so I don't know if this is relevant, but, just FYI, when I built invoicer-chapter2 with Go 1.13 on CircleCI, I got the error below ... Changing "%d" to "%s" fixed it, which may make sense because mux.Vars is a map[string]string ...

#!/bin/bash -eo pipefail
go test \
github.com/${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}

# github.com/******/invoicer-chapter2
./main.go:122:3: httpError format %d has arg vars["id"] of wrong type string

Exited with code exit status 2