安装golang的保护套时出现问题

I have some code. But when I try run cover test and have response:

'go get -u github.com/gregoryv/uncover/...
go test -coverprofile /tmp/c.out
uncover /tmp/c.out'

I try install cover package:

go get code.google.com/p/go.tools/cmd/cover

but get error

package code.google.com/p/go.tools/cmd/cover: unrecognized import path "code.google.com/p/go.tools/cmd/cover" (parse https://code.google.com/p/go.tools/cmd/cover?go-get=1: no go-import meta tags (meta tag github.com/golang/go did not match import path code.google.com/p/go.tools/cmd/cover))

System: Ubuntu 18.04

The correct path is:

go get golang.org/x/tools/cmd/cover