case err := <-c:
		if err == nil {
			t.Error("error expected")
		} else if err != io.ErrNoProgress {
			t.Error("unexpected error:", err)
		}
	case <-time.After(time.Second):
		t.Error("test timed out (endless loop in ReadByte?)")
	}
}

// A StringReader delivers its data one string segment at a time via Read.
type StringReader struct {
	data []string
	step int
}