Function TestRaceAttributedToPassingTest

cmd/testwrapper/testwrapper_test.go:279–321

TestRaceAttributedToPassingTest covers the case where go test attributes a data race report to a test that itself reports PASS (e.g. when the racing goroutines outlive the test that spawned them and TSan prints during a different test's window). Without the race-detection fix, the WARNING: DATA RACE

(t *testing.T)

// stuck in a passing test's log buffer and dropped on the floor.
// See https://github.com/tailscale/tailscale/issues/19603.
func TestRaceAttributedToPassingTest(t *testing.T) {
	if runtime.GOOS != "linux" || runtime.GOARCH != "amd64" {
		t.Skip("test requires the race detector, which needs linux/amd64")
	}
	t.Parallel()

	testfile := filepath.Join(t.TempDir(), "race_test.go")
	code := []byte(`package race_test

import (
	"sync"
	"testing"
)

var counter int
var wg sync.WaitGroup

func TestSpawn(t *testing.T) {
	wg.Add(2)
	go func() { defer wg.Done(); counter++ }()
	go func() { defer wg.Done(); counter++ }()
}

func TestWait(t *testing.T) {
	wg.Wait()
}
`)
	if err := os.WriteFile(testfile, code, 0o644); err != nil {
		t.Fatalf("writing package: %s", err)
	}

	out, err := cmdTestwrapper(t, testfile, "-race").CombinedOutput()
	if code, ok := errExitCode(err); !ok || code != 1 {
		t.Fatalf("testwrapper %s -race: expected exit code 1, got %v; output was:\n%s", testfile, err, out)
	}
	if want := "WARNING: DATA RACE"; !bytes.Contains(out, []byte(want)) {
		t.Fatalf("expected race report in output, got:\n%s", out)
	}

	if testing.Verbose() {
		t.Logf("success - output:\n%s", out)
	}
}

func TestBuildError(t *testing.T) {
	t.Parallel()