dirGIDFile := filepath.Join(setgiddir, "setgid")
	if err := sh.moveOrCopyFile(dirGIDFile, pkgfile.Name(), 0666, true); err != nil {
		t.Fatalf("moveOrCopyFile: %v", err)
	}

	got := strings.TrimSpace(cmdBuf.String())
	want := sh.fmtCmd("", "cp %s %s", pkgfile.Name(), dirGIDFile)
	if got != want {
		t.Fatalf("moveOrCopyFile(%q, %q): want %q, got %q", dirGIDFile, pkgfile.Name(), want, got)
	}