added progressionIndicator and corrsponding test

app/lib/bad_connection.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_svg/flutter_svg.dart';
+
+class BadConnection extends StatelessWidget {
+  const BadConnection();
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: MediaQuery.of(context).size.width,
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: <Widget>[
+          SvgPicture.asset(
+            'assets/bad_connection.svg',
+            height: 300.0,
+          ),
+          const Padding(
+            padding: EdgeInsets.all(8.0),
+            child: Text('Bad Connection: Unable to reach the avary'),
+          ),
+        ],
+      ),
+    );
+  }
+}

app/lib/posts_list.dart

@@ -1,5 +1,5 @@
 import 'package:flutter/material.dart';
-
+import 'bad_connection.dart';
 import 'models/post.dart';
 import 'no_content.dart';
 import 'post_item.dart';
@@ -15,12 +15,12 @@ class PostsList extends StatelessWidget {
       stream: posts,
       builder: (BuildContext context, AsyncSnapshot<List<Post>> snapshot) {
         if (snapshot.hasError) {
-          return Text('Error: ${snapshot.error}');
+          return const BadConnection();
         }
 
         switch (snapshot.connectionState) {
           case ConnectionState.waiting:
-            return const Text('Loading...');
+            return const CircularProgressIndicator();
           default:
             if (snapshot.data.isEmpty) {
               return const NoContent();

app/pubspec.yaml

@@ -52,6 +52,7 @@ flutter:
   assets:
     - assets/undraw_a_day_at_the_park_owg1.svg
     - assets/google_g_logo.png
+    - assets/bad_connection.svg
 
   # An image asset can refer to one or more resolution-specific "variants", see
   # https://flutter.io/assets-and-images/#resolution-aware.

app/test/bad_connection_test.dart

@@ -0,0 +1,17 @@
+import 'package:birb/bad_connection.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_svg/flutter_svg.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Renders content', (WidgetTester tester) async {
+    // Build our app and trigger a frame.
+    await tester.pumpWidget(const MaterialApp(
+      home: BadConnection(),
+    ));
+
+    expect(find.byType(SvgPicture), findsOneWidget);
+    expect(
+        find.text('Bad Connection: Unable to reach the avary'), findsOneWidget);
+  });
+}

app/test/posts_list_test.dart

@@ -16,7 +16,7 @@ void main() {
           home: PostsList(mockPosts(count: 5)),
         ));
 
-        expect(find.text('Loading...'), findsOneWidget);
+        expect(find.byType(CircularProgressIndicator), findsOneWidget);
 
         await tester.pump(Duration.zero);
 
@@ -34,14 +34,15 @@ void main() {
       expect(find.byType(NoContent), findsOneWidget);
     });
 
-    testWidgets('renders NoContent widget', (WidgetTester tester) async {
+    testWidgets('renders BadConnection widget', (WidgetTester tester) async {
       // Build our app and trigger a frame.
       await tester.pumpWidget(MaterialApp(
         home: PostsList(Future<List<Post>>.error('Bad Connection').asStream()),
       ));
       await tester.pump(Duration.zero);
 
-      expect(find.text('Error: Bad Connection'), findsOneWidget);
+      expect(find.text('Bad Connection: Unable to reach the avary'),
+          findsOneWidget);
     });
   });
 }