Add tests

lib/app.dart

@@ -4,8 +4,12 @@ import 'package:thesis_shop/screens/cart/cart_screen.dart';
 import 'package:thesis_shop/screens/product_list/product_list_screen.dart';
 import 'package:thesis_shop/service/product_service.dart';
 import 'package:thesis_shop/stores/store_injector.dart';
+import 'package:thesis_shop/stores/user_store.dart';
 import 'package:thesis_shop/utils/map_keys_extension.dart';
 
+import 'stores/cart_store.dart';
+import 'stores/product_store.dart';
+
 class ThesisShopApp extends StatelessWidget {
   final ProductService productService;
   const ThesisShopApp({Key? key, required this.productService})
@@ -13,8 +17,13 @@ class ThesisShopApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final userStore = UserStore();
+    final productStore = ProductStore(productService, userStore);
+    final cartStore = CartStore(productStore);
     return StoreInjector(
-      productService: productService,
+      cartStore: cartStore,
+      userStore: userStore,
+      productStore: productStore,
       child: MaterialApp(
         title: 'Thesis Shop',
         theme: ThemeData(primarySwatch: Colors.red),

lib/screens/cart/total_price_text.dart

@@ -1,16 +1,22 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_mobx/flutter_mobx.dart';
+import 'package:thesis_shop/stores/store_injector.dart';
 
 class TotalPriceText extends StatelessWidget {
   const TotalPriceText({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
+    final cartStore = StoreInjector.of(context).cartStore;
     return SafeArea(
       child: Padding(
         padding: const EdgeInsets.all(8.0),
-        child: Text(
-          'Gesamtpreis: 27€',
-          style: Theme.of(context).textTheme.labelLarge?.copyWith(fontSize: 24),
+        child: Observer(
+          builder: (context) => Text(
+            'Gesamtpreis: ${cartStore.totalPrice.toStringAsFixed(2)}€',
+            style:
+                Theme.of(context).textTheme.labelLarge?.copyWith(fontSize: 24),
+          ),
         ),
       ),
     );

lib/stores/cart_store.dart

@@ -32,6 +32,12 @@ abstract class _CartStore with Store {
   @computed
   int get numberOfItems => cart.length;
 
+  @computed
+  double get totalPrice => cart.fold(
+      0.0,
+      (previousValue, element) =>
+          previousValue + element.amount * element.product.price);
+
   @action
   void _changeAmountOfProduct(Product product, int amount) {
     final oldValue = _productQuantities.putIfAbsent(product.title, () => 0);

lib/stores/cart_store.g.dart

@@ -23,6 +23,13 @@ mixin _$CartStore on _CartStore, Store {
       (_$numberOfItemsComputed ??= Computed<int>(() => super.numberOfItems,
               name: '_CartStore.numberOfItems'))
           .value;
+  Computed<double>? _$totalPriceComputed;
+
+  @override
+  double get totalPrice =>
+      (_$totalPriceComputed ??= Computed<double>(() => super.totalPrice,
+              name: '_CartStore.totalPrice'))
+          .value;
 
   final _$_productQuantitiesAtom = Atom(name: '_CartStore._productQuantities');
 
@@ -56,7 +63,8 @@ mixin _$CartStore on _CartStore, Store {
   String toString() {
     return '''
 cart: ${cart},
-numberOfItems: ${numberOfItems}
+numberOfItems: ${numberOfItems},
+totalPrice: ${totalPrice}
     ''';
   }
 }

lib/stores/store_injector.dart

@@ -1,22 +1,20 @@
 import 'package:flutter/widgets.dart';
-import 'package:thesis_shop/service/product_service.dart';
 import 'package:thesis_shop/stores/cart_store.dart';
 import 'package:thesis_shop/stores/product_store.dart';
 import 'package:thesis_shop/stores/user_store.dart';
 
 class StoreInjector extends InheritedWidget {
-  final UserStore userStore = UserStore();
-  late final CartStore cartStore;
-  late final ProductStore productStore;
+  final UserStore userStore;
+  final CartStore cartStore;
+  final ProductStore productStore;
 
-  StoreInjector({
+  const StoreInjector({
     Key? key,
-    required ProductService productService,
+    required this.userStore,
+    required this.cartStore,
+    required this.productStore,
     required Widget child,
-  }) : super(key: key, child: child) {
-    productStore = ProductStore(productService, userStore);
-    cartStore = CartStore(productStore);
-  }
+  }) : super(key: key, child: child);
 
   static StoreInjector of(BuildContext context) {
     final StoreInjector? result =

test/cart_store_test.dart

@@ -0,0 +1,25 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobx/mobx.dart';
+import 'package:mobx/src/api/async.dart';
+import 'package:thesis_shop/models/product.dart';
+import 'package:thesis_shop/stores/cart_store.dart';
+import 'package:thesis_shop/stores/product_store.dart';
+
+import 'product_service_mock.dart';
+
+class MockedProductStore implements ProductStore {
+  @override
+  void loadProducts() {}
+
+  @override
+  ObservableFuture<List<Product>> products =
+      ObservableFuture.value(demoProducts);
+}
+
+void main() {
+  test('test cart store', () {
+    final cartStore = CartStore(MockedProductStore());
+    cartStore.incrementAmountOfProduct(demoProducts.first);
+    expect(cartStore.amountOfProduct(demoProducts.first), 1);
+  });
+}

test/product_service_mock.dart

@@ -1,15 +1,17 @@
 import 'package:thesis_shop/models/product.dart';
 import 'package:thesis_shop/service/product_service.dart';
 
+const demoProducts = [
+  Product(title: 'Bananen', price: 3),
+  Product(title: 'Äpfel', price: 2),
+  Product(title: 'Birnen', price: 2.5),
+  Product(title: 'Kirschen', price: 1.2),
+];
+
 class MockedProductService implements ProductService {
   @override
   Future<List<Product>> fetchProducts() async {
-    return const [
-      Product(title: 'Bananen', price: 3),
-      Product(title: 'Äpfel', price: 2),
-      Product(title: 'Birnen', price: 2.5),
-      Product(title: 'Kirschen', price: 1.2),
-    ];
+    return demoProducts;
   }
 
   @override

test/total_price_text_test.dart

@@ -0,0 +1,55 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mobx/src/api/observable_collections.dart';
+import 'package:thesis_shop/models/cart_item.dart';
+import 'package:thesis_shop/models/product.dart';
+import 'package:thesis_shop/screens/cart/total_price_text.dart';
+import 'package:thesis_shop/stores/cart_item_store.dart';
+import 'package:thesis_shop/stores/cart_store.dart';
+import 'package:thesis_shop/stores/store_injector.dart';
+import 'package:thesis_shop/stores/user_store.dart';
+
+import 'cart_store_test.dart';
+
+class MockedCartStore implements CartStore {
+  @override
+  int amountOfProduct(Product product) {
+    throw UnimplementedError();
+  }
+
+  @override
+  ObservableList<CartItem> get cart => throw UnimplementedError();
+
+  @override
+  CartItemStore cartItemStoreOfProduct(Product product) {
+    throw UnimplementedError();
+  }
+
+  @override
+  void decrementAmountOfProduct(Product product) {}
+
+  @override
+  void incrementAmountOfProduct(Product product) {}
+
+  @override
+  int get numberOfItems => throw UnimplementedError();
+
+  @override
+  double get totalPrice => 10.0;
+}
+
+void main() {
+  testWidgets('test total price text', (tester) async {
+    await tester.pumpWidget(
+      StoreInjector(
+        userStore: UserStore(),
+        cartStore: MockedCartStore(),
+        productStore: MockedProductStore(),
+        child: const MaterialApp(
+          home: TotalPriceText(),
+        ),
+      ),
+    );
+    expect(find.text('Gesamtpreis: 10.00€'), findsOneWidget);
+  });
+}