}

func (w *teststringwriter) WriteString(s string) (int, error) {
	w.writeString += s
	return len(s), nil
}

func (w *teststringwriter) check(t *testing.T, write, writeString string) {
	t.Helper()
	if w.write != write {
		t.Errorf("write: expected %q, got %q", write, w.write)
	}
	if w.writeString != writeString {
		t.Errorf("writeString: expected %q, got %q", writeString, w.writeString)
	}
}