proposal: testing: add Test function

[rogpeppe]

The testing package has long contained the Benchmark function, which allows code in a non-testing source file to run benchmarks.

It is sometimes useful to be able to run test code in a non-testing context too; for example to demonstrate a failing test in the Go playground.

Perhaps something like this?

// Test runs f as a test with the given name. Any test output
// is written to w. Test reports whether the test has succeeded.
func Test(w io.Writer, name string, f func(t *testing.T)) bool

[josharian]

See also #6511

There is work in progress now to allow multiple files in the playground, which should make this better yet.

[rsc]

I had no idea that https://play.golang.org/p/LnHfX2yF4Oe worked, but it does. (We should write clearer docs for the playground - @bradfitz will file a bug.)

Given that https://play.golang.org/p/LnHfX2yF4Oe does work, @rogpeppe, is there still much rationale for adding testing.Test?

[bradfitz]

I filed #32294

[rsc]

Looking at this again I am surprised that GitHub says I closed this. I suspect I clicked the wrong button again. I intended to leave it open for @rogpeppe to respond.

[rogpeppe]

Thanks Russ - the close did feel a little sudden :) The playground was my main motivation behind raising this issue, so I think it's OK to close this issue. I might remember another use case in time though.