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testing: invalid testing.go:1343: test executed panic(nil) or runtime.Goexit: subtest may have called FailNow on a parent test error #58129
Description
$ go version
I use play.golang.org website.
Does this issue reproduce with the latest release?
Yes.
What operating system and processor architecture are you using (go env)?
I use play.golang.org website.
What did you do?
I run this test
https://go.dev/play/p/BtIQcyQJYxR
What did you expect to see?
I expected to see this
=== RUN TestRunFatal
=== RUN TestRunFatal/Alex
prog_test.go:11: Alex
--- FAIL: TestRunFatal (0.00s)
--- FAIL: TestRunFatal/Alex (0.00s)
FAIL
Program exited.
This output is from slightly modified version of my test
https://go.dev/play/p/QeGIM_xxA4E
What did you see instead?
I see this
=== RUN TestRunFatal
=== RUN TestRunFatal/Alex
=== CONT TestRunFatal
prog_test.go:11: Alex
=== CONT TestRunFatal/Alex
testing.go:1343: test executed panic(nil) or runtime.Goexit: subtest may have called FailNow on a parent test
--- FAIL: TestRunFatal (0.00s)
--- FAIL: TestRunFatal/Alex (0.00s)
FAIL
Program exited.
Perhaps I don't understand how tests work. But I was surprised and confused by the
testing.go:1343: test executed panic(nil) or runtime.Goexit: subtest may have called FailNow on a parent test
error message. I also tried reading testing.FailNow documentation at
https://pkg.go.dev/testing#T.FailNow
The documentation talks about goroutines, but I don't have any goroutines in my test.
Thank you for investigating this.
Alex
Activity
qiulaidongfeng commentedon Jan 29, 2023
Document in https://pkg.go.dev/testing#T.Run
Run runs f as a subtest of t called name. It runs f in a separate goroutine and blocks until f returns or calls t.Parallel to become a parallel test.
Document in https://pkg.go.dev/testing#T.Fatal
Fatal is equivalent to Log followed by FailNow.
https://go.dev/play/p/BtIQcyQJYxR A new goroutine is opened in the code t.Run() of. In this goroutine, TestRunFatal's t.Fatal() calls TestRunFatal's t.FailNow(). This is expected behavior.
alexbrainman commentedon Jan 29, 2023
Maybe you are correct @qiulaidongfeng .
Alex
mknyszek commentedon Jan 30, 2023
That's right, this behavior is expected. The test captures
tfrom the parent test and fails it from the subtest, which isn't allowed (because it's not on that test's goroutine).mknyszek commentedon Jan 30, 2023
On the topic of error messages and documentation, I think this could probably be a bit clearer, or have an example. I wonder if any of the go.dev tutorials point this out.