TestMain prevents other tests from running

[pascal-blokur]

Go version

go version go1.24.4 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN='/home/pascal/go/bin'
GOCACHE='/home/pascal/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/pascal/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1468475678=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/pascal/go/src/github.com/pascal/awesomeProject/go.mod'
GOMODCACHE='/home/pascal/go/pkg/mod'
GONOPROXY='github.com/blokur/*'
GONOSUMDB='github.com/blokur/*'
GOOS='linux'
GOPATH='/home/pascal/go'
GOPRIVATE='github.com/blokur/*'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/pascal/go/installs/latest/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='on'
GOTELEMETRYDIR='/home/pascal/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/pascal/go/installs/latest/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

Suppose I have these two files:

main.go:

package main

func main() { 
}

main_test.go:

package main

import (
	"testing"
)

func TestMain(m *testing.M) {
	println("main")
}

func TestFatal(t *testing.T) {
	println("fatal")
	t.Fatal("foo")
}

func TestHappy(t *testing.T) {
	println("happy")
}

If I test the package, I get ok (which is strange, as my TestFatal should fail)

> go test -v 
main
ok  	github.com/pascal/awesomeProject	0.002s

However, if I remove the TestMain function from the file, and then run it again:

> go test -v
=== RUN   TestFatal
fatal
    main_test.go:9: foo
--- FAIL: TestFatal (0.00s)
=== RUN   TestHappy
happy
--- PASS: TestHappy (0.00s)
FAIL
exit status 1
FAIL    github.com/pascal/awesomeProject        0.002s

What did you see happen?

Running the test with the TestMain function seems to have prevented the TestFatal from running

What did you expect to see?

I expected the TestFatal to cause go test -v to fail when TestMain and TestFatal were present in the file.
(I also kind of expected the -v to display TestMain)

[seankhliao]

https://pkg.go.dev/testing#hdr-Main

TestMain runs in the main goroutine and can do whatever setup and teardown is necessary around a call to m.Run

it is your responsibility to actually start running the tests if you use TestMain.

Unlike many projects, the Go project does not use GitHub Issues for general discussion or asking questions. GitHub Issues are used for tracking bugs and proposals only.

For questions please refer to https://github.com/golang/go/wiki/Questions

[pascal-blokur]

Adding m.Run() in TestMain solves it, as explained. Thanks.

[gabyhelp]

Related Issues

• cmd/go: go test quietly skips test if custom flag is defined #36527 (closed)
• testing: panics in example tests abort remaining tests #48009 (closed)
• testing: when using a custom TestMain, m.Run does not return if one of the tests it runs panics #37206
• go test ./... fail when two hierarchy both use TestMain(m *testing.T) #17394 (closed)
• x/tools/go/packages: _test packages cannot be loaded directly #66444 (closed)
• testing: odd interaction between -json flag and TestMain #31969 (closed)
• testing: t.Fatal does not fatal tests if defers do not complete #22989 (closed)
• Can't find package test #39937 (closed)
• testing: nested t.Fatalf hides errors #22882 (closed)
• cmd/go: invoking go run from go test can corrupt build cache #69566

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