Terminate owned subprocess trees

internal/adapters/subprocess/run_test.go

@@ -3,6 +3,7 @@ package subprocess
 import (
 	"context"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -368,6 +369,24 @@ func TestSubprocessHelper(t *testing.T) {
 		key := os.Getenv("SUBPROCESS_HELPER_ENV_KEY")
 		_, _ = os.Stdout.WriteString(os.Getenv(key) + "\n")
 		os.Exit(0)
+	case "tree":
+		descendant := exec.Command(os.Args[0], "-test.run=^TestSubprocessHelper$", "--", "descendant")
+		descendant.Env = append(os.Environ(), "GO_WANT_SUBPROCESS_HELPER=1")
+		descendant.Stdout = os.Stdout
+		descendant.Stderr = os.Stderr
+		if err := descendant.Start(); err != nil {
+			os.Exit(3)
+		}
+		if err := os.WriteFile(os.Getenv("SUBPROCESS_HELPER_READY_PATH"), []byte("ready"), 0o600); err != nil {
+			os.Exit(4)
+		}
+		time.Sleep(10 * time.Second)
+		os.Exit(0)
+	case "descendant":
+		time.Sleep(500 * time.Millisecond)
+		_ = os.WriteFile(os.Getenv("SUBPROCESS_HELPER_SENTINEL_PATH"), []byte("survived"), 0o600)
+		time.Sleep(10 * time.Second)
+		os.Exit(0)
 	default:
 		os.Exit(2)
 	}