package main import ( "bytes" "image" "image/color" "image/png" "testing" "github.com/stretchr/testify/require" ) func imageTestPNG(t *testing.T, width, height int) []byte { t.Helper() picture := image.NewRGBA(image.Rect(0, 0, width, height)) picture.Set(0, 0, color.RGBA{ R: 255, A: 255, }) var data bytes.Buffer require.NoError(t, png.Encode(&data, picture)) return data.Bytes() }