Test for plugins/inputs/riemann_listener fails with go 1.16 with unexpected call to os.Exit(0) during test

[sergiodj]

System info:

I'm testing telegraf 1.17.2 on Ubuntu Hirsute (development release) with golang-go 1.16.

Steps to reproduce:

Basically, build telegraf and the run its testsuite.

Expected behavior:

Everything should pass, as usual.

Actual behavior:

I started seeing the following failure:

2021/02/20 05:27:33 Entering
2021/02/20 05:27:33 I! [] Listening on tcp://127.0.0.1:5555
--- FAIL: TestSocketListener_tcp (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(0x8502e0, 0x94c2c0)
	/usr/lib/go-1.16/src/testing/testing.go:1144 +0x332
testing.tRunner.func1(0xc000001b00)
	/usr/lib/go-1.16/src/testing/testing.go:1147 +0x4b6
panic(0x8502e0, 0x94c2c0)
	/usr/lib/go-1.16/src/runtime/panic.go:965 +0x1b9
os.Exit(0x0)
	/usr/lib/go-1.16/src/os/proc.go:68 +0x6d
github.com/influxdata/telegraf/plugins/inputs/riemann_listener.(*RiemannSocketListener).Stop(0xc0001a8000)
	/<<BUILDDIR>>/telegraf-1.17.2+ds1/plugins/inputs/riemann_listener/riemann_listener.go:390 +0x65
github.com/influxdata/telegraf/plugins/inputs/riemann_listener.TestSocketListener_tcp(0xc000001b00)
	/<<BUILDDIR>>/telegraf-1.17.2+ds1/plugins/inputs/riemann_listener/riemann_listener_test.go:30 +0x1b8
testing.tRunner(0xc000001b00, 0x8ef9b8)
	/usr/lib/go-1.16/src/testing/testing.go:1194 +0xef
created by testing.(*T).Run
	/usr/lib/go-1.16/src/testing/testing.go:1239 +0x2b3
FAIL	github.com/influxdata/telegraf/plugins/inputs/riemann_listener	0.043s

This seems to happen because of https://tip.golang.org/doc/go1.16#go-test. There's a similar issue (with the corresponding PR) here: posener/complete#132

[srebhan]

I'm pretty sure this is an actual case! Looking at rieman_listener's Stop() function

func (rsl *RiemannSocketListener) Stop() {
	rsl.wg.Done()
	rsl.wg.Wait()
	os.Exit(0)
}

I rather have to hold my breath... :-S We need to fix it...

[sspaink]

Ok I removed os.Exit(0) call in #8882, I think just removing it should be fine doesn't look like it needs any extra steps.