Add err handling tests for encode/decode versioned bytes functions

pkg/loop/internal/chain_reader.go

@@ -37,7 +37,7 @@ func encodeVersionedBytes(data any, version int32) (*pb.VersionedBytes, error) {
 			return nil, err
 		}
 	default:
-		return nil, fmt.Errorf("Unsupported encoding version %d for data %v", version, data)
+		return nil, fmt.Errorf("unsupported encoding version %d for data %v", version, data)
 	}
 
 	return &pb.VersionedBytes{Version: SimpleJsonEncodingVersion, Data: jsonData}, nil
@@ -51,7 +51,7 @@ func decodeVersionedBytes(res any, vData *pb.VersionedBytes) error {
 			return err
 		}
 	default:
-		return fmt.Errorf("Unsupported encoding version %d for versionedData %v", vData.Version, vData.Data)
+		return fmt.Errorf("unsupported encoding version %d for versionedData %v", vData.Version, vData.Data)
 	}
 
 	return nil

pkg/loop/internal/chain_reader_test.go

@@ -0,0 +1,46 @@
+package internal
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/smartcontractkit/chainlink-relay/pkg/loop/internal/pb"
+)
+
+func TestVersionedBytesFunctionsBadPaths(t *testing.T) {
+	t.Run("EncodeVersionedBytes unsupported type", func(t *testing.T) {
+		expected := errors.New("json: unsupported type: chan int")
+		invalidData := make(chan int)
+
+		_, err := encodeVersionedBytes(invalidData, SimpleJsonEncodingVersion)
+		if err == nil || err.Error() != expected.Error() {
+			t.Errorf("expected error: %s, but got: %v", expected, err)
+		}
+	})
+
+	t.Run("EncodeVersionedBytes unsupported encoding version", func(t *testing.T) {
+		expected := errors.New("unsupported encoding version 2 for data map[key:value]")
+		data := map[string]interface{}{
+			"key": "value",
+		}
+
+		_, err := encodeVersionedBytes(data, 2)
+		if err == nil || err.Error() != expected.Error() {
+			t.Errorf("expected error: %s, but got: %v", expected, err)
+		}
+	})
+
+	t.Run("DecodeVersionedBytes", func(t *testing.T) {
+		var decodedData map[string]interface{}
+		expected := errors.New("unsupported encoding version 2 for versionedData [97 98 99 100 102]")
+		versionedBytes := &pb.VersionedBytes{
+			Version: 2, // Unsupported version
+			Data:    []byte("abcdf"),
+		}
+
+		err := decodeVersionedBytes(&decodedData, versionedBytes)
+		if err == nil || err.Error() != expected.Error() {
+			t.Errorf("expected error: %s, but got: %v", expected, err)
+		}
+	})
+}