fix: loading fonts performance issue (#170)

* adds local cache to know when a font family was already loaded to avoid processing

* adds multiple icons tests

Author: gustavobelo-dev

example/test/widgets/multiple_icons_golden_test.dart

@@ -0,0 +1,100 @@
+import 'package:alchemist/alchemist.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('Multiple icons test >', () {
+    final iconsMap = <String, IconData>{
+      'add': Icons.add,
+      'alarm': Icons.alarm,
+      'android': Icons.android,
+      'arrow_back': Icons.arrow_back,
+      'arrow_forward': Icons.arrow_forward,
+      'build': Icons.build,
+      'call': Icons.call,
+      'camera_alt': Icons.camera_alt,
+      'check': Icons.check,
+      'close': Icons.close,
+      'delete': Icons.delete,
+      'done': Icons.done,
+      'edit': Icons.edit,
+      'favorite': Icons.favorite,
+      'home': Icons.home,
+      'info': Icons.info,
+      'menu': Icons.menu,
+      'more_vert': Icons.more_vert,
+      'notifications': Icons.notifications,
+      'phone': Icons.phone,
+      'search': Icons.search,
+      'settings': Icons.settings,
+      'share': Icons.share,
+      'shopping_cart': Icons.shopping_cart,
+      'star': Icons.star,
+      'accessibility': Icons.accessibility,
+      'accessible': Icons.accessible,
+      'account_circle': Icons.account_circle,
+      'account_box': Icons.account_box,
+      'add_box': Icons.add_box,
+      'add_circle': Icons.add_circle,
+      'add_shopping_cart': Icons.add_shopping_cart,
+      'airplanemode_active': Icons.airplanemode_active,
+      'album': Icons.album,
+      'all_inbox': Icons.all_inbox,
+      'analytics': Icons.analytics,
+      'archive': Icons.archive,
+      'arrow_drop_down': Icons.arrow_drop_down,
+      'arrow_drop_up': Icons.arrow_drop_up,
+      'assessment': Icons.assessment,
+      'attach_file': Icons.attach_file,
+      'attachment': Icons.attachment,
+      'auto_fix_high': Icons.auto_fix_high,
+      'backup': Icons.backup,
+      'battery_full': Icons.battery_full,
+      'bed': Icons.bed,
+      'book': Icons.book,
+      'bookmark': Icons.bookmark,
+      'brightness_4': Icons.brightness_4,
+      'business': Icons.business,
+      'calendar_today': Icons.calendar_today,
+      'camera': Icons.camera,
+      'card_giftcard': Icons.card_giftcard,
+      'card_membership': Icons.card_membership,
+      'chat': Icons.chat,
+      'check_box': Icons.check_box,
+      'chevron_left': Icons.chevron_left,
+      'chevron_right': Icons.chevron_right,
+      'cloud': Icons.cloud,
+      'cloud_queue': Icons.cloud_queue,
+      'code': Icons.code,
+      'commute': Icons.commute,
+      'compare_arrows': Icons.compare_arrows,
+      'credit_card': Icons.credit_card,
+      'crop_square': Icons.crop_square,
+      'dashboard': Icons.dashboard,
+      'directions': Icons.directions,
+      'directions_bike': Icons.directions_bike,
+      'directions_car': Icons.directions_car,
+      'directions_walk': Icons.directions_walk,
+      'download': Icons.download,
+      'event': Icons.event,
+      'exit_to_app': Icons.exit_to_app,
+      'face': Icons.face,
+      'fingerprint': Icons.fingerprint,
+    };
+
+    for (final iconEntry in iconsMap.entries) {
+      goldenTest(
+        'should render icon ${iconEntry.key} correctly',
+        fileName: 'icons/${iconEntry.key}',
+        skip: true, // removes if you want to check loading fonts performance
+        builder: () => GoldenTestScenario.builder(
+          name: iconEntry.key,
+          builder: (_) => Icon(
+            iconEntry.value,
+            size: 64,
+          ),
+        ),
+      );
+    }
+  });
+}

lib/src/golden_test.dart

@@ -11,6 +11,8 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:meta/meta.dart';
 
+final Set<String> _loadedFontFamilies = {};
+
 /// Default golden test runner which uses the flutter test framework.
 const defaultGoldenTestRunner = FlutterGoldenTestRunner();
 GoldenTestRunner _goldenTestRunner = defaultGoldenTestRunner;
@@ -44,6 +46,11 @@ Future<void> loadFonts() async {
     final family = (entry['family'] as String)
         .stripFontFamilyAlchemistPackageName();
 
+    // Skip if font family is already loaded
+    if (_loadedFontFamilies.contains(family)) {
+      continue;
+    }
+
     final fontAssets = [
       for (final fontAssetEntry in entry['fonts'] as List<dynamic>)
         (fontAssetEntry as Map<String, dynamic>)['asset'] as String,
@@ -55,6 +62,7 @@ Future<void> loadFonts() async {
     }
 
     await loader.load();
+    _loadedFontFamilies.add(family);
   }
 }