cmd/go: "go test" accepts -test.FLAG where FLAG is any flag accepted by "go build"

[minux]

This behavior always existed from Go 1.0.

For example:

$ go test image -test.work
WORK=/tmp/go-build271188011
ok  	image	0.361s

Is this expected? I find it quite confusing as there is no -test.work flag documented anywhere and it conflicts with user defined -test.FLAG flags. If this is WAI, we probably should document it.

[rsc]

Yes, we should definitely fix this, but I think it's too late for Go 1.9.

[rsc]

/cc @bcmills

[bcmills]

I think CL 211358 will fix this.

[gopherbot]

Change https://golang.org/cl/211358 mentions this issue: cmd/go/internal/{test,vet}: use a standard flag.FlagSet to parse flags