r := NewReader(rw)
		if _, err := r.WriteTo(rw); err != rw.expected {
			t.Errorf("r.WriteTo(errorWriterToTests[%d]) = _, %v, want _,%v", i, err, rw.expected)
		}
	}
}

func TestWriterReadFrom(t *testing.T) {
	ws := []func(io.Writer) io.Writer{
		func(w io.Writer) io.Writer { return onlyWriter{w} },
		func(w io.Writer) io.Writer { return w },
	}

	rs := []func(io.Reader) io.Reader{