testing.M failed to satisfy ut that calls os.Exit(0) twice.

[njuptlzf]

What version of Go are you using (go version)?

$ go version
go version go1.16.2 linux/amd64

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

Ubuntu 5.4.0-6ubuntu1~16.04.12)

What did you do?

Use testing.M to test a case that may return os.Exit(0).
There are two cases to call os.Exit(0).

What did you expect to see?

In the file, all cases are executed, and the execution results of all cases are correctly expressed.

What did you see instead?

Execute to the first os.Exit(0), ut exits.

[davecheney]

Can you please include a runnable example to demonstrate the problem. Thank you.

[njuptlzf]

demo:

package test0418

import (
	"log"
	"os"
	"testing"
)

func TestMain(m *testing.M) {
	log.Println("Do stuff BEFORE the tests!")
	m.Run()
	log.Println("Do stuff AFTER the tests!")
}

func TestA(t *testing.T) {
	log.Println("TestA running")
	os.Exit(0)
}

func TestB(t *testing.T) {
	log.Println("TestB running")
	os.Exit(1)
}

func TestC(t *testing.T) {
	log.Println("TestC running")
}

run:

# go test .
2021/04/18 17:59:08 Do stuff BEFORE the tests!
2021/04/18 17:59:08 TestA running
--- FAIL: TestA (0.00s)
panic: unexpected call to os.Exit(0) during test [recovered]
        panic: unexpected call to os.Exit(0) during test

goroutine 6 [running]:
testing.tRunner.func1.2(0x51e980, 0x5701d8)
        /root/go/go/src/testing/testing.go:1144 +0x332
testing.tRunner.func1(0xc000001380)
        /root/go/go/src/testing/testing.go:1147 +0x4b6
panic(0x51e980, 0x5701d8)
        /root/go/go/src/runtime/panic.go:965 +0x1b9
os.Exit(0x0)
        /root/go/go/src/os/proc.go:68 +0x6d
test.TestA(0xc000001380)
        /home/go_project/test/test0418/testM_test.go:18 +0x6a
testing.tRunner(0xc000001380, 0x5517c8)
        /root/go/go/src/testing/testing.go:1194 +0xef
created by testing.(*T).Run
        /root/go/go/src/testing/testing.go:1239 +0x2b3
FAIL    test    0.006s
FAIL
# echo $?
1

I expect to execute all possible use cases for os.Exit(int), and if only int==0, the overall success. Because sometimes even calling os.Exit(0) is an expected behavior.
Otherwise, it seems that I can only consider using mock?

[davecheney]

test's shouldn't call os.Exit. If you want to abort the test use t.FailNow()

[ianlancetaylor]

Closing this issue because this working as intended. If a test calls os.Exit, the test binary will exit, and go test will report a failure.