codebeat: Code quality improvement (#103)

* codebeat: improve & bugfix

* codebeat: refactor to improve readability

* bugfix

* bugfix

* internal/data/codec: improve code coverage

internal/data/codec/encoder_test.go

@@ -0,0 +1,29 @@
+package codec
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+
+	"github.com/prologic/bitcask/internal"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEncode(t *testing.T) {
+	t.Parallel()
+	assert := assert.New(t)
+
+	var buf bytes.Buffer
+	encoder := NewEncoder(&buf)
+	_, err := encoder.Encode(internal.Entry{
+		Key:      []byte("mykey"),
+		Value:    []byte("myvalue"),
+		Checksum: 414141,
+		Offset:   424242,
+	})
+
+	expectedHex := "0000000500000000000000076d796b65796d7976616c7565000651bd"
+	if assert.NoError(err) {
+		assert.Equal(expectedHex, hex.EncodeToString(buf.Bytes()))
+	}
+}