New creates a new temporary location, either for a go module or for a gopath root.

NewGoModule creates a new go module root in the system temporary location, creates the root dir and the go.mod file.

NewGoRoot creates a new gopath in the system temporary location, creates the src dir and the namespace dir.

Builder can be used in testing to create a temporary go module or gopath, src, namespace and package directory, and populate it with source files.