// we write a file to the cache indicating that all test results from before
		// right now are to be ignored.
		dir, _ := cache.DefaultDir()
		if dir != "off" {
			f, err := lockedfile.Edit(filepath.Join(dir, "testexpire.txt"))
			if err == nil {
				now := time.Now().UnixNano()
				buf, _ := io.ReadAll(f)
				prev, _ := strconv.ParseInt(strings.TrimSpace(string(buf)), 10, 64)
				if now > prev {

	// instead of searching out and deleting test result cache entries.)
	if dir, _ := cache.DefaultDir(); dir != "off" {
		if data, _ := lockedfile.Read(filepath.Join(dir, "testexpire.txt")); len(data) > 0 && data[len(data)-1] == '\n' {
			if t, err := strconv.ParseInt(string(data[:len(data)-1]), 10, 64); err == nil {
				testCacheExpire = time.Unix(0, t)
			}
		}
	}