@bcmills @rsc

@jadekler at the bottom of go help test you will see:

For more about specifying packages, see 'go help packages'

Within go help packages you will see:

- "all" expands to all packages found in all the GOPATH
trees. For example, 'go list all' lists all the packages on the local
system. When using modules, "all" expands to all packages in
the main module and their dependencies, including dependencies
needed by tests of any of those.

Hopefully that answers things so I'll close this issue; please shout if that's not the case.

Thanks for the reply @myitcv. I do not think that is sufficient, but we're close. Consider that when I type go test github.com/foo/bar, I know that I'm dealing with a package. However, if I'm moderately unaware of modules (1), go test all is cryptic. What is "all"? A bit of guessing and extrapolation arrives at the answer: all packages.

However, guesswork and extrapolation too often ends in frustration instead of enlightenment. We can cut all of that out with a greppable note that's as simple as this:

Note that 'go test all' runs tests against all packages. For more information,
see 'go help packages'.

1: Which is hopefully 90% of users! If we can make them as unobtrusive as possible. :)

e.g. https://go-review.googlesource.com/c/go/+/134095

Change https://golang.org/cl/134095 mentions this issue: cmd/test: add documentation for 'go test all'