Why would you not test your code with the same RDBMS you will have in production? Especially if it’s something as easy to install as Postgres? It seems like begging for trouble...
$ time go test github.com/sapcc/limes/... | grep -v 'no test files'
ok github.com/sapcc/limes 0.004s
ok github.com/sapcc/limes/pkg/api 0.515s
ok github.com/sapcc/limes/pkg/collector 0.449s
ok github.com/sapcc/limes/pkg/core 0.006s
I doubt that you can setup and tear down several dozen Postgreses in that time.