test(sr): add golden tests for font family transform

packages/datadog_session_replay/example/golden_test/font_family_transform_golden_test.dart

@@ -0,0 +1,174 @@
+// Unless explicitly stated otherwise all files in this repository are licensed under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2025-Present Datadog, Inc.
+
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+
+import 'package:datadog_common_test/datadog_common_test.dart';
+import 'package:datadog_session_replay/datadog_session_replay.dart';
+import 'package:datadog_session_replay/src/capture/capture_node.dart';
+import 'package:datadog_session_replay/src/capture/recorder.dart';
+import 'package:datadog_session_replay/src/datadog_session_replay_platform_interface.dart';
+import 'package:datadog_session_replay/src/rum_context.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_test_goldens/flutter_test_goldens.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+import 'golden_test_helpers.dart';
+
+class MockDatadogSessionReplayPlatform extends Mock
+    with MockPlatformInterfaceMixin
+    implements DatadogSessionReplayPlatform {}
+
+void main() {
+  late SessionReplayRecorder recorder;
+  late RUMContext context;
+  late MockDatadogSessionReplayPlatform platform;
+
+  setUpAll(() async {
+    await TestFonts.loadAppFonts();
+  });
+
+  setUp(() {
+    recorder = SessionReplayRecorder(
+      defaultCapturePrivacy: TreeCapturePrivacy(
+        textAndInputPrivacyLevel: TextAndInputPrivacyLevel.maskSensitiveInputs,
+        imagePrivacyLevel: ImagePrivacyLevel.maskNone,
+      ),
+      touchPrivacyLevel: TouchPrivacyLevel.show,
+    );
+    platform = MockDatadogSessionReplayPlatform();
+    DatadogSessionReplayPlatform.instance = platform;
+
+    registerFallbackValue(
+      CapturedViewAttributes(paintBounds: Rect.zero, scaleX: 1.0, scaleY: 1.0),
+    );
+
+    context = RUMContext(
+      applicationId: randomString(),
+      sessionId: randomString(),
+    );
+    recorder.updateContext(context);
+  });
+
+  testWidgets('font transform smart maps package font to open sans',
+      (tester) async {
+    final fixture = MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text(
+            'Font Transform Test',
+            style: TextStyle(fontFamily: 'packages/my_app/CustomFont'),
+          ),
+        ),
+        body: Padding(
+          padding: const EdgeInsets.all(12.0),
+          child: Text(
+            'This text uses a package font that gets transformed to OpenSans '
+            'by the font family transform. If you see readable text in the '
+            'golden, the transform is working correctly.',
+            style: TextStyle(
+              fontFamily: 'packages/my_app/CustomFont',
+              fontSize: 16,
+            ),
+          ),
+        ),
+      ),
+    );
+    await snapshotTest(
+      tester,
+      recorder,
+      fixture,
+      fontFamilyTransform: FontFamilyTransformConfig(
+        strategy: FontFamilyStrategy.smart,
+        rules: {
+          'CustomFont': TestFonts.openSans,
+        },
+      ),
+    );
+  });
+
+  testWidgets('font transform smart drops sentinel and uses fallback rule',
+      (tester) async {
+    final fixture = MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text(
+            'Sentinel Transform',
+            style: TextStyle(fontFamily: '.AppleSystemUIFont'),
+          ),
+        ),
+        body: Padding(
+          padding: const EdgeInsets.all(12.0),
+          child: Text(
+            'This text uses .AppleSystemUIFont which the smart strategy '
+            'drops as a Flutter sentinel. The empty-key fallback rule then '
+            'maps it to OpenSans. Readable text proves sentinel handling works.',
+            style: TextStyle(
+              fontFamily: '.AppleSystemUIFont',
+              fontSize: 16,
+            ),
+          ),
+        ),
+      ),
+    );
+    await snapshotTest(
+      tester,
+      recorder,
+      fixture,
+      fontFamilyTransform: FontFamilyTransformConfig(
+        strategy: FontFamilyStrategy.smart,
+        rules: {
+          '': TestFonts.openSans,
+        },
+      ),
+    );
+  });
+
+  testWidgets('font transform fallback replaces all families',
+      (tester) async {
+    final fixture = MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text(
+            'Fallback Strategy',
+            style: TextStyle(fontFamily: TestFonts.openSans),
+          ),
+        ),
+        body: Padding(
+          padding: const EdgeInsets.all(12.0),
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Text(
+                'OpenSans text stays the same font stack with fallback.',
+                style: TextStyle(
+                  fontFamily: TestFonts.openSans,
+                  fontSize: 16,
+                ),
+              ),
+              SizedBox(height: 12),
+              Text(
+                'Custom font text also gets the fallback stack.',
+                style: TextStyle(
+                  fontFamily: 'packages/my_app/CustomFont',
+                  fontSize: 16,
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    await snapshotTest(
+      tester,
+      recorder,
+      fixture,
+      fontFamilyTransform: const FontFamilyTransformConfig(
+        strategy: FontFamilyStrategy.fallback,
+      ),
+    );
+  });
+}

packages/datadog_session_replay/example/golden_test/golden_test_helpers.dart

@@ -5,6 +5,7 @@
 import 'dart:typed_data';
 
 import 'package:datadog_flutter_plugin/datadog_flutter_plugin.dart';
+import 'package:datadog_session_replay/datadog_session_replay.dart';
 import 'package:datadog_session_replay/src/capture/recorder.dart';
 import 'package:datadog_session_replay/src/processor/processor_worker.dart';
 import 'package:datadog_session_replay/src/sr_data_models.dart';
@@ -61,9 +62,11 @@ Future<void> snapshotTest(
   SessionReplayRecorder recorder,
   Widget fixture, {
   TestActions? testActions,
+  FontFamilyTransformConfig fontFamilyTransform =
+      const FontFamilyTransformConfig(),
 }) async {
   DatadogSdk.instance.sdkVerbosity = CoreLoggerLevel.debug;
-  final processor = ProcessorWorker();
+  final processor = ProcessorWorker(fontFamilyTransform: fontFamilyTransform);
   await tester.pumpWidget(
     SimpleTestCapture(key: Key('key'), recorder: recorder, child: fixture),
   );