test(app): 前端第一批测试 — EditorBloc 19用例 + JournalElement 11用例 + InMemoryRepo 12用例

添加 mocktail 测试依赖 + 字体文件占位
总计 42 测试通过，覆盖工具/笔画/元素/撤销/重做/序列化/乐观锁/CRUD

app/test/data/models/journal_element_test.dart

@@ -0,0 +1,202 @@
+// JournalElement 模型单元测试
+//
+// 覆盖：工厂方法、便利工厂、copyWith 不可变性、序列化往返、默认值
+
+import 'dart:math';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:nuanji_app/data/models/journal_element.dart';
+
+void main() {
+  group('JournalElement', () {
+    // ===== create 工厂 =====
+
+    test('create 工厂生成正确的默认值', () {
+      final element = JournalElement.create(
+        journalId: 'journal-1',
+        elementType: ElementType.text,
+        positionX: 10,
+        positionY: 20,
+        content: {'text': 'Hello'},
+      );
+
+      expect(element.journalId, 'journal-1');
+      expect(element.elementType, ElementType.text);
+      expect(element.positionX, 10.0);
+      expect(element.positionY, 20.0);
+      expect(element.width, 100.0);
+      expect(element.height, 100.0);
+      expect(element.rotation, 0.0);
+      expect(element.zIndex, 0);
+      expect(element.version, 1);
+      expect(element.id, isNotEmpty);
+      expect(element.createdAt, isNotNull);
+      expect(element.updatedAt, isNotNull);
+    });
+
+    // ===== createText =====
+
+    test('createText 便利工厂', () {
+      final element = JournalElement.createText(
+        journalId: 'j-1',
+        text: '你好',
+        position: const Offset(50, 100),
+        fontSize: 24.0,
+        fontColor: '#E07A5F',
+      );
+
+      expect(element.elementType, ElementType.text);
+      expect(element.content['text'], '你好');
+      expect(element.content['fontSize'], 24.0);
+      expect(element.content['fontColor'], '#E07A5F');
+      expect(element.positionX, 50.0);
+      expect(element.positionY, 100.0);
+    });
+
+    test('createText 使用默认字号和颜色', () {
+      final element = JournalElement.createText(
+        journalId: 'j-1',
+        text: '默认',
+        position: Offset.zero,
+      );
+
+      expect(element.content['fontSize'], 18.0);
+      expect(element.content['fontColor'], '#2D2420');
+    });
+
+    // ===== createImage =====
+
+    test('createImage 便利工厂', () {
+      final element = JournalElement.createImage(
+        journalId: 'j-1',
+        filePath: '/path/to/image.jpg',
+        position: Offset.zero,
+        thumbnailPath: '/path/to/thumb.jpg',
+      );
+
+      expect(element.elementType, ElementType.image);
+      expect(element.content['filePath'], '/path/to/image.jpg');
+      expect(element.content['thumbnailPath'], '/path/to/thumb.jpg');
+    });
+
+    test('createImage 无 thumbnailPath 时不包含该字段', () {
+      final element = JournalElement.createImage(
+        journalId: 'j-1',
+        filePath: '/path/to/img.jpg',
+        position: Offset.zero,
+      );
+
+      expect(element.content.containsKey('thumbnailPath'), isFalse);
+      expect(element.content['filePath'], '/path/to/img.jpg');
+    });
+
+    // ===== createSticker =====
+
+    test('createSticker 便利工厂', () {
+      final element = JournalElement.createSticker(
+        journalId: 'j-1',
+        emoji: '🐱',
+        position: const Offset(50, 50),
+        stickerPackId: 'pack-1',
+        stickerId: 's-1',
+      );
+
+      expect(element.elementType, ElementType.sticker);
+      expect(element.content['emoji'], '🐱');
+      expect(element.content['stickerPackId'], 'pack-1');
+      expect(element.content['stickerId'], 's-1');
+    });
+
+    test('createSticker 无可选字段时不包含', () {
+      final element = JournalElement.createSticker(
+        journalId: 'j-1',
+        emoji: '🌸',
+        position: Offset.zero,
+      );
+
+      expect(element.content.containsKey('stickerPackId'), isFalse);
+      expect(element.content.containsKey('stickerId'), isFalse);
+      expect(element.content['emoji'], '🌸');
+    });
+
+    // ===== copyWith 不可变性 =====
+
+    test('copyWith 返回新实例且不修改原始', () {
+      final original = JournalElement.createText(
+        journalId: 'j-1',
+        text: '原始',
+        position: Offset.zero,
+      );
+
+      final modified = original.copyWith(
+        positionX: 100.0,
+        positionY: 200.0,
+      );
+
+      expect(identical(original, modified), isFalse);
+      expect(original.positionX, 0.0);
+      expect(original.positionY, 0.0);
+      expect(modified.positionX, 100.0);
+      expect(modified.positionY, 200.0);
+      expect(modified.journalId, original.journalId);
+      expect(modified.id, original.id);
+    });
+
+    // ===== 序列化 =====
+
+    test('toJson / fromJson 往返一致', () {
+      final original = JournalElement.createText(
+        journalId: 'j-1',
+        text: '序列化测试',
+        position: const Offset(42, 84),
+        fontSize: 20.0,
+      );
+
+      final json = original.toJson();
+      final restored = JournalElement.fromJson(json);
+
+      expect(restored.id, original.id);
+      expect(restored.journalId, original.journalId);
+      expect(restored.elementType, original.elementType);
+      expect(restored.positionX, original.positionX);
+      expect(restored.positionY, original.positionY);
+      expect(restored.content['text'], original.content['text']);
+      expect(restored.version, original.version);
+    });
+
+    test('fromJson 处理空 content', () {
+      final json = {
+        'id': 'test-id',
+        'journal_id': 'j-1',
+        'element_type': 'text',
+        'position_x': 0.0,
+        'position_y': 0.0,
+        'width': 100.0,
+        'height': 100.0,
+        'rotation': 0.0,
+        'z_index': 0,
+        'content': <String, dynamic>{},
+        'version': 1,
+        'created_at': DateTime.now().toIso8601String(),
+        'updated_at': DateTime.now().toIso8601String(),
+      };
+
+      final element = JournalElement.fromJson(json);
+      expect(element.content, isA<Map>());
+      expect(element.content, isEmpty);
+    });
+
+    // ===== ElementType 枚举 =====
+
+    test('ElementType 枚举值完整', () {
+      expect(ElementType.values.length, 5);
+      expect(ElementType.values, containsAll([
+        ElementType.text,
+        ElementType.image,
+        ElementType.sticker,
+        ElementType.handwritingRef,
+        ElementType.tape,
+      ]));
+    });
+  });
+}