move codec-specific utilities into pkg/codecs

pkg/codecs/jpeg/start_of_frame1_test.go

@@ -0,0 +1,49 @@
+package jpeg
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var casesStartOfFrame1 = []struct {
+	name string
+	enc  []byte
+	dec  StartOfFrame1
+}{
+	{
+		"base",
+		[]byte{
+			0xff, 0xc0, 0x0, 0x11, 0x8, 0x2, 0x58, 0x3,
+			0x20, 0x3, 0x0, 0x22, 0x0, 0x1, 0x11, 0x1,
+			0x2, 0x11, 0x1,
+		},
+		StartOfFrame1{
+			Type:                   1,
+			Width:                  800,
+			Height:                 600,
+			QuantizationTableCount: 2,
+		},
+	},
+}
+
+func TestStartOfFrame1Unmarshal(t *testing.T) {
+	for _, ca := range casesStartOfFrame1 {
+		t.Run(ca.name, func(t *testing.T) {
+			var h StartOfFrame1
+			err := h.Unmarshal(ca.enc[4:])
+			require.NoError(t, err)
+			h.QuantizationTableCount = 2
+			require.Equal(t, ca.dec, h)
+		})
+	}
+}
+
+func TestStartOfFrame1Marshal(t *testing.T) {
+	for _, ca := range casesStartOfFrame1 {
+		t.Run(ca.name, func(t *testing.T) {
+			byts := ca.dec.Marshal(nil)
+			require.Equal(t, ca.enc, byts)
+		})
+	}
+}