proposal: testing: add pid to -json output

[josharian]

Proposal Details

I have been playing with test output processors.

The obvious way to run them is:

go test ./... -json | the_test_tool

But the tool now has very little ability to cancel the actual test processes being run. It's all or nothing: close stdin, or don't.

As a result, many such processors want pole position: the_test_tool ./.... That's less ideal, because it doesn't compose nicely; for example, it doesn't play nicely with go test -c.

I propose that when -json is provided, each test process emits a line containing its pid. (Maybe something like "Action": "Info", "PID": 12345?)

Then test tools, particularly interactive test tools, can kill individual test processes as needed.