test: setup unit test for flutter_skin main class and CI check on PRs

.github/workflows/pr_verification_pipeline.yml

@@ -2,20 +2,23 @@ on:
   pull_request:
     branches: [ "main" ]
 jobs:
-
-  analyze-code:
+  dart_format_and_analyze:
+    name: dart format and analyze
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Install Flutter
-        uses: subosito/flutter-action@v2
+      - uses: actions/checkout@v4
+      - uses: subosito/flutter-action@v2
         with:
           channel: stable
-      - name: Install dependencies
-        run: flutter pub get
-
+
+      - name: Run pub get
+        run: dart pub get
+
+      - name: Verify formatting
+        run: dart format --output=none --set-exit-if-changed .
+
       - name: Running Flutter analysis on package code
-        run: flutter analyze --no-fatal-infos --no-fatal-warnings --write=analysis_report.txt
+        run: flutter analyze --no-fatal-warnings --write=analysis_report.txt
 
       - name: Artifact analysis report
         uses: actions/upload-artifact@v4
@@ -24,4 +27,38 @@ jobs:
           name: analysis-report
           path: |
             analysis_report.txt
-          retention-days: 15
+          retention-days: 15
+
+  unit-test:
+    needs: dart_format_and_analyze
+    name: Run unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Run unit tests
+        run: flutter test
+
+  dry-run-upload:
+    needs: unit-test
+    name: Dry run upload
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Check Publish Warnings
+        run: dart pub publish --dry-run

lib/constants/fskin_constants.dart

@@ -1,3 +1,4 @@
 class FskinConstants {
   static const String baseUrl = 'fskinbackend-production.up.railway.app';
+  static const String keyRegex = r'^fsk_[a-f0-9]{64}$';
 }

lib/flutter_skin.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart' show ThemeData, ColorScheme;
 import 'package:flutter/widgets.dart';
+import 'package:flutter_skin/constants/fskin_constants.dart';
 import 'package:flutter_skin/models/project_config.dart';
 import 'package:flutter_skin/remote/fskin_remote_config.dart';
 import 'package:flutter_skin/services/fskin_logger.dart';
@@ -10,7 +11,8 @@ class FlutterSkin with WidgetsBindingObserver {
 
   late String apiKey;
   static final FskinSubscriber _sse = FskinSubscriber();
-  static Stream<ThemeData> get onSkinChanged => FskinRemoteConfig.onSkinChanged;
+  static FskinRemoteConfig remoteConfig = FskinRemoteConfig.singleton;
+  static Stream<ThemeData> get onSkinChanged => remoteConfig.onSkinChanged;
   static final FskinLogger _logger = FskinLogger();
 
   // Private constructor
@@ -20,7 +22,11 @@ class FlutterSkin with WidgetsBindingObserver {
     if (apiKey.trim().isEmpty) {
       _logger.logError('apiKey must not be empty');
       throw ArgumentError.value(apiKey, 'apiKey', 'apiKey must not be empty');
+    } else if (RegExp(FskinConstants.keyRegex).hasMatch(apiKey) == false) {
+      _logger.logError('apiKey is not valid');
+      throw ArgumentError.value(apiKey, 'apiKey', 'apiKey is not valid');
     }
+
     if (_instance == null) {
       _instance = FlutterSkin._();
       WidgetsBinding.instance.addObserver(_instance!);
@@ -48,7 +54,7 @@ class FlutterSkin with WidgetsBindingObserver {
     );
     _sse.listen(
       apiKey: _instance!.apiKey,
-      onSkinUpdated: FskinRemoteConfig.singleton.fetchConfig,
+      onSkinUpdated: remoteConfig.fetchConfig,
     );
   }
 
@@ -58,7 +64,7 @@ class FlutterSkin with WidgetsBindingObserver {
     if (state == AppLifecycleState.resumed) {
       try {
         _logger.logMessage('Fetching latest config and restarting stream.');
-        await FskinRemoteConfig.singleton.fetchConfig();
+        await remoteConfig.fetchConfig();
       } finally {
         _startStream();
       }
@@ -73,7 +79,7 @@ class FlutterSkin with WidgetsBindingObserver {
   /// Query current active theme from remote config and return as ThemeData.
   /// When there's no active theme, the result is null or fallbackTheme if provided.
   static ThemeData? toThemeData({ThemeData? fallbackTheme}) {
-    ProjectConfig? config = FskinRemoteConfig.projectConfig;
+    ProjectConfig? config = remoteConfig.projectConfig;
     ColorScheme? colors = config?.skin?.colors;
     ThemeData remoteTheme = ThemeData(colorScheme: colors);
     if (colors == null) {
@@ -91,6 +97,22 @@ class FlutterSkin with WidgetsBindingObserver {
   /// Query current active theme from remote config and return as ThemeData.
   /// When there's no active theme, the result is null.
   static ThemeData? get theme {
+    if (_instance == null) {
+      throw Exception(
+        'FlutterSkin must be initialized with FlutterSkin.init()',
+      );
+    }
     return toThemeData();
   }
+
+  @visibleForTesting
+  static void resetInstance() {
+    _instance = null;
+    FlutterSkin.remoteConfig = FskinRemoteConfig.singleton;
+  }
+
+  @visibleForTesting
+  void setRemoteConfig(FskinRemoteConfig remoteConfig) {
+    FlutterSkin.remoteConfig = remoteConfig;
+  }
 }

lib/remote/fskin_remote_config.dart

@@ -15,9 +15,9 @@ class FskinRemoteConfig {
   late String apiKey;
   ProjectConfig? _cachedConfig;
 
-  static Stream<ThemeData> get onSkinChanged => _skinController.stream;
+  Stream<ThemeData> get onSkinChanged => _skinController.stream;
 
-  static ProjectConfig? get projectConfig {
+  ProjectConfig? get projectConfig {
     if (_instance == null) {
       throw Exception(
         'FskinRemoteConfig must be initialized with FskinRemoteConfig.init()',

lib/services/skin_service.dart

@@ -28,7 +28,7 @@ class SkinService {
             body: jsonEncode({'apiKey': apiKey}),
           )
           .timeout(const Duration(seconds: 5));
-        
+
       _logger.logMessage(
         'Received response with status code: ${response.statusCode}',
       );

pubspec.yaml

@@ -20,6 +20,7 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_lints: ^6.0.0
+  mockito: ^5.5.0
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

test/flutter_skin/flutter_skin_init_test.dart

@@ -0,0 +1,68 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_skin/flutter_skin.dart';
+import 'package:flutter_skin/models/project_config.dart';
+import 'package:flutter_skin/remote/fskin_remote_config.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+
+import '../mocks/skin_model_mocks.dart';
+
+class MockFskinRemoteConfig extends Mock implements FskinRemoteConfig {}
+
+class MockProjectConfig extends Mock implements ProjectConfig {}
+
+void main() async {
+  group('FlutterSkin Initialization Tests', () {
+    final apiKey =
+        'fsk_1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef';
+
+    setUp(() async {
+      TestWidgetsFlutterBinding.ensureInitialized();
+      await FlutterSkin.init(apiKey: apiKey);
+    });
+
+    test('fetches and applies skin on successful response', () async {
+      // Testing with fake api key will result in null theme.
+      await FlutterSkin.init(apiKey: apiKey);
+
+      final skin = FlutterSkin.theme;
+      final instance = FlutterSkin.singleton;
+
+      expect(instance.apiKey, apiKey);
+      expect(skin, null);
+    });
+
+    test('applies skin from remote config', () async {
+      final instance = FlutterSkin.singleton;
+
+      instance.setRemoteConfig(MockFskinRemoteConfig());
+      when(
+        FlutterSkin.remoteConfig.projectConfig,
+      ).thenReturn(ProjectConfig(skin: skinModelMock));
+
+      final skin = FlutterSkin.theme;
+      expect(instance.apiKey, apiKey);
+      expect(skin, isA<ThemeData>());
+      expect(skin?.colorScheme.primary, skinModelMock.colors?.primary);
+    });
+
+    test('project config returns a nullable skin', () async {
+      final instance = FlutterSkin.singleton;
+
+      instance.setRemoteConfig(MockFskinRemoteConfig());
+      when(
+        FlutterSkin.remoteConfig.projectConfig,
+      ).thenReturn(MockProjectConfig());
+
+      var skin = FlutterSkin.theme;
+      expect(instance.apiKey, apiKey);
+      expect(skin, isA<Null>());
+
+      skin = FlutterSkin.toThemeData(
+        fallbackTheme: ThemeData(primaryColor: Colors.red),
+      );
+      expect(skin, isA<ThemeData>());
+      expect(skin?.brightness, Brightness.light);
+    });
+  });
+}

test/flutter_skin/initialization_scenario_test.dart

@@ -0,0 +1,34 @@
+import 'package:flutter_skin/flutter_skin.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('Initialization test across different scenarios', () {
+    test(
+      'should throw an exception if init is called with an empty apiKey',
+      () async {
+        expect(
+          () => FlutterSkin.init(apiKey: ''),
+          throwsA(isA<ArgumentError>()),
+        );
+      },
+    );
+
+    test(
+      'should throw an exception if init is called with an invalid apiKey',
+      () async {
+        expect(
+          () => FlutterSkin.init(apiKey: 'my_api_key'),
+          throwsA(isA<ArgumentError>()),
+        );
+      },
+    );
+
+    test('should throw an exception if singleton is accessed before init', () {
+      expect(() => FlutterSkin.singleton, throwsA(isA<Exception>()));
+    });
+
+    test('should throw an exception if theme is accessed before init', () {
+      expect(() => FlutterSkin.theme, throwsA(isA<Exception>()));
+    });
+  });
+}

test/mocks/skin_model_mocks.dart

@@ -0,0 +1,22 @@
+// ignore_for_file: deprecated_member_use
+
+import 'package:flutter/material.dart';
+import 'package:flutter_skin/models/skin_model.dart';
+
+var skinModelMock = SkinModel(
+  colors: const ColorScheme.light(
+    primary: Color(0xFF6200EE),
+    secondary: Color(0xFF03DAC6),
+    background: Color(0xFFFFFFFF),
+    surface: Color(0xFFFFFFFF),
+    onPrimary: Color(0xFFFFFFFF),
+    onSecondary: Color(0xFF000000),
+    onBackground: Color(0xFF000000),
+    onSurface: Color(0xFF000000),
+  ),
+  id: 'mock_id',
+  projectId: 'mock_project_id',
+  isActive: true,
+  version: 1,
+  createdAt: DateTime.now(),
+);