chore: add a basic test suite

Author: mcquenji

test/modular_widget_test.dart

@@ -0,0 +1,127 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
+import 'package:flutter_modular/flutter_modular.dart';
+import 'package:flutter_modular_widget/flutter_modular_widget.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mcquenji_core/mcquenji_core.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  late TestRepository repository;
+
+  setUp(() {
+    Modular.init(_TestModule());
+    repository = Modular.get<TestRepository>();
+  });
+
+  tearDown(() {
+    cleanGlobals();
+  });
+
+  Future<void> pumpHarness(
+    WidgetTester tester, {
+    void Function(TestRepository repo)? onContentBuild,
+  }) async {
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: _TestHarness(onContentBuild: onContentBuild),
+      ),
+    );
+    await tester.pump();
+  }
+
+  testWidgets('shows loader while watched repository is loading', (
+    tester,
+  ) async {
+    await pumpHarness(tester);
+
+    expect(find.text('loader'), findsOneWidget);
+  });
+
+  testWidgets('renders derived content once repository provides data', (
+    tester,
+  ) async {
+    await pumpHarness(tester);
+    repository.setData(7);
+    await tester.pump(Duration(milliseconds: 1000));
+
+    expect(find.text('content: 7'), findsOneWidget);
+  });
+
+  testWidgets('renders error UI when repository enters error state', (
+    tester,
+  ) async {
+    await pumpHarness(tester);
+    repository.setData(1);
+    await tester.pump();
+    await tester.pump();
+
+    repository.setError(Exception('boom'));
+    await tester.pump();
+    await tester.pump();
+
+    expect(find.text('error: Exception: boom'), findsOneWidget);
+  });
+
+  testWidgets('exposes non-reactive repository access via get callback', (
+    tester,
+  ) async {
+    TestRepository? repoSeenInContent;
+
+    await pumpHarness(
+      tester,
+      onContentBuild: (repo) => repoSeenInContent = repo,
+    );
+
+    repository.setData(42);
+    await tester.pump(Duration(milliseconds: 100));
+
+    expect(repoSeenInContent, same(repository));
+  });
+}
+
+class _TestHarness extends ModularWidget<int> {
+  const _TestHarness({this.onContentBuild});
+
+  final void Function(TestRepository repo)? onContentBuild;
+
+  @override
+  Widget buildLoader(BuildContext context) => const Text('loader');
+
+  @override
+  Widget buildError(
+    BuildContext context,
+    Object error,
+    StackTrace? stackTrace,
+  ) => Text('error: $error');
+
+  @override
+  Widget buildContent(BuildContext context, int data, RepoAccessor get) {
+    onContentBuild?.call(get<TestRepository>());
+    return Text('content: $data');
+  }
+
+  @override
+  FutureOr<int> query(RepoAccessor watch) {
+    final repo = watch<TestRepository>();
+    return repo.state.requireData;
+  }
+}
+
+class _TestModule extends Module {
+  @override
+  void binds(Injector i) {
+    i.addRepository<TestRepository>(TestRepository.new);
+  }
+}
+
+class TestRepository extends Repository<AsyncValue<int>> {
+  TestRepository() : super(AsyncValue.loading());
+
+  void setData(int value) => emit(AsyncValue.data(value));
+
+  void setError(Object error) => emit(AsyncValue.error(error));
+}