t.Errorf("got uncompressed data length %d, want %d", n, tc.datalen)
					}
				}

				i += chunkFieldsLength + int(length)
			}
		})

	}
}

func TestWriterLevels(t *testing.T) {
	m := image.NewNRGBA(image.Rect(0, 0, 100, 100))

	var b1, b2 bytes.Buffer
	if err := (&Encoder{}).Encode(&b1, m); err != nil {
		t.Fatal(err)
	}