From c442124248089e3f2f56904e712f5051bdfe9381 Mon Sep 17 00:00:00 2001
From: Ales Verbic <verbotenj@blinklabs.io>
Date: Fri, 11 Oct 2024 20:32:27 -0400
Subject: [PATCH] feat: add MarshalJson support for ByteString and Blake2b224
 with tests (#756)

Signed-off-by: Ales Verbic <verbotenj@blinklabs.io>
---
 cbor/bytestring.go           |  6 ++++
 cbor/bytestring_test.go      | 60 ++++++++++++++++++++++++++++++++++++
 ledger/common/common.go      |  4 +++
 ledger/common/common_test.go | 36 ++++++++++++++++++++++
 4 files changed, 106 insertions(+)
 create mode 100644 cbor/bytestring_test.go

diff --git a/cbor/bytestring.go b/cbor/bytestring.go
index 7ea38db1..1b7fd501 100644
--- a/cbor/bytestring.go
+++ b/cbor/bytestring.go
@@ -16,6 +16,7 @@ package cbor
 
 import (
 	"encoding/hex"
+	"encoding/json"
 
 	_cbor "github.com/fxamacker/cbor/v2"
 )
@@ -36,3 +37,8 @@ func NewByteString(data []byte) ByteString {
 func (bs ByteString) String() string {
 	return hex.EncodeToString(bs.Bytes())
 }
+
+// MarshalJSON converts ByteString to a JSON-compatible string
+func (bs ByteString) MarshalJSON() ([]byte, error) {
+	return json.Marshal(bs.String())
+}
diff --git a/cbor/bytestring_test.go b/cbor/bytestring_test.go
new file mode 100644
index 00000000..8060f879
--- /dev/null
+++ b/cbor/bytestring_test.go
@@ -0,0 +1,60 @@
+// Copyright 2023 Blink Labs Software
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package cbor
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// Test the String method to ensure it properly converts ByteString to hex.
+func TestByteString_String(t *testing.T) {
+	data := []byte("blinklabs") // "blinklabs" as bytes
+	bs := NewByteString(data)
+
+	expected := "626c696e6b6c616273" // "blinklabs" in hex
+	actual := bs.String()
+
+	if actual != expected {
+		t.Errorf("expected %s but got %s", expected, actual)
+	}
+}
+
+// Test the MarshalJSON method to ensure it properly marshals ByteString to JSON as hex.
+func TestByteString_MarshalJSON(t *testing.T) {
+	data := []byte("blinklabs") // "blinklabs" as bytes
+	bs := NewByteString(data)
+
+	jsonData, err := json.Marshal(bs)
+	if err != nil {
+		t.Fatalf("failed to marshal ByteString: %v", err)
+	}
+
+	// Expected JSON result, hex-encoded string
+	expectedJSON := `"626c696e6b6c616273"` // "blinklabs" in hex
+
+	if string(jsonData) != expectedJSON {
+		t.Errorf("expected %s but got %s", expectedJSON, string(jsonData))
+	}
+}
+
+// Test NewByteString to ensure it properly wraps the byte slice
+func TestNewByteString(t *testing.T) {
+	data := []byte{0x41, 0x42, 0x43} // "ABC" in hex
+	bs := NewByteString(data)
+
+	if string(bs.Bytes()) != "ABC" {
+		t.Errorf("expected ABC but got %s", string(bs.Bytes()))
+	}
+}
diff --git a/ledger/common/common.go b/ledger/common/common.go
index 98bc9fff..0d84b49a 100644
--- a/ledger/common/common.go
+++ b/ledger/common/common.go
@@ -78,6 +78,10 @@ func (b Blake2b224) Bytes() []byte {
 	return b[:]
 }
 
+func (b Blake2b224) MarshalJSON() ([]byte, error) {
+	return json.Marshal(b.String())
+}
+
 // Blake2b224Hash generates a Blake2b-224 hash from the provided data
 func Blake2b224Hash(data []byte) Blake2b224 {
 	tmpHash, err := blake2b.New(Blake2b224Size, nil)
diff --git a/ledger/common/common_test.go b/ledger/common/common_test.go
index 3ca1ab64..a4eba4a8 100644
--- a/ledger/common/common_test.go
+++ b/ledger/common/common_test.go
@@ -125,3 +125,39 @@ func TestMultiAssetJson(t *testing.T) {
 		}
 	}
 }
+
+// Test the MarshalJSON method for Blake2b224 to ensure it properly converts to JSON.
+func TestBlake2b224_MarshalJSON(t *testing.T) {
+	// Example data to represent Blake2b224 hash
+	data := []byte("blinklabs")
+	hash := NewBlake2b224(data)
+
+	// Blake2b224 always produces 28 bytes (224 bits) as its output.
+	// Expected JSON value: the hex-encoded string of "blinklabs" padded to fit 28 bytes.
+	// JSON marshalling adds quotes around the string, so include quotes in expected value.
+	expected := `"626c696e6b6c61627300000000000000000000000000000000000000"`
+
+	// Marshal the Blake2b224 object to JSON
+	jsonData, err := json.Marshal(hash)
+	if err != nil {
+		t.Fatalf("failed to marshal Blake2b224: %v", err)
+	}
+
+	// Compare the result with the expected output
+	if string(jsonData) != expected {
+		t.Errorf("expected %s but got %s", expected, string(jsonData))
+	}
+}
+
+func TestBlake2b224_String(t *testing.T) {
+	data := []byte("blinklabs") // Less than 28 bytes
+	hash := NewBlake2b224(data)
+
+	// Expected hex string for "blinklabs" padded/truncated to fit 28 bytes
+	expected := "626c696e6b6c61627300000000000000000000000000000000000000"
+
+	// Verify if String() gives the correct hex-encoded string
+	if hash.String() != expected {
+		t.Errorf("expected %s but got %s", expected, hash.String())
+	}
+}