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proposal: testing: allow TestMain to return int #23404
Description
Currently TestMain is expected to call os.Exit itself, but that means it's
not possible to use defer to do package-wide test cleanup there,
because the defer will never be called.
I propose that TestMain be optionally allowed to return an integer,
in which case os.Exit will be called with its result.
Then we can write:
func TestMain(m *testing.M) int {
defer testhelper.Cleanup()
return m.Run()
}
which is arguably more natural and harder to get wrong than calling os.Exit.
Activity
mvdan commentedon Jan 10, 2018
Playing the devil's advocate - if one wants to be sure that
os.Exitcan't interfere with defers, what about something like:I understand that this is more verbose, but I'm wondering if that offsets adding extra code and documentation to the testing package. I would definitely agree with you if the testing package was designed from the ground up, however. Unless there is a specific reason for
os.Exitthat we are both missing.OneOfOne commentedon Jan 10, 2018
@mvdan
os.Exitis required to indicate tests success or failure iirc.mvdan commentedon Jan 10, 2018
@OneOfOne what is your point? The integer that you can use in an os.Exit call is the same integer that @rogpeppe suggests to have as a return parameter. See my silly workaround above as an example.
rsc commentedon Jan 29, 2018
TestMain is already a rare need. It doesn't make much sense to stack another one on top, especially when you can do what @mvdan suggests.