[adaptive_scaffold] : 🐛 : #110902 : Assertion added when try with less that 2 destinations. (#6360)

*Issue : flutter/flutter#110902

Changes included in PR are listed as follows
- As `NavigationRail` & `NavigationBar` etc has assertion which won't allow less than 2 destinations, Similar assertion added in "AdaptiveScaffold" to acknowledge users regarding the same with a user friendly message.
- CHANGELOG.md file updated.
- Updated to v0.1.10

Author: aliasgar4558

packages/flutter_adaptive_scaffold/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.1.10
+
+* FIX : Assertion added when tried with less than 2 destinations - [flutter/flutter#110902](https://github.com/flutter/flutter/issues/110902)
+
 ## 0.1.9
 
 * FIX : Drawer stays open even on destination tap - [flutter/flutter#141938](https://github.com/flutter/flutter/issues/141938)

packages/flutter_adaptive_scaffold/lib/src/adaptive_scaffold.dart

@@ -103,7 +103,10 @@ class AdaptiveScaffold extends StatefulWidget {
     this.navigationRailWidth = 72,
     this.extendedNavigationRailWidth = 192,
     this.appBarBreakpoint,
-  });
+  }) : assert(
+          destinations.length >= 2,
+          'At least two destinations are required',
+        );
 
   /// The destinations to be used in navigation items. These are converted to
   /// [NavigationRailDestination]s and [BottomNavigationBarItem]s and inserted

packages/flutter_adaptive_scaffold/pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_adaptive_scaffold
 description: Widgets to easily build adaptive layouts, including navigation elements.
-version: 0.1.9
+version: 0.1.10
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+flutter_adaptive_scaffold%22
 repository: https://github.com/flutter/packages/tree/main/packages/flutter_adaptive_scaffold
 

packages/flutter_adaptive_scaffold/test/adaptive_scaffold_test.dart

@@ -257,9 +257,9 @@ void main() {
       ];
 
       await tester.pumpWidget(
-        const MaterialApp(
+        MaterialApp(
           home: MediaQuery(
-            data: MediaQueryData(size: Size(700, 900)),
+            data: const MediaQueryData(size: Size(700, 900)),
             child: AdaptiveScaffold(
               destinations: destinations,
             ),
@@ -717,6 +717,33 @@ void main() {
       expect(appBar, findsOneWidget);
     },
   );
+
+  testWidgets(
+    'When only one destination passed, shall throw assertion error',
+    (WidgetTester tester) async {
+      const List<NavigationDestination> destinations = <NavigationDestination>[
+        NavigationDestination(
+          icon: Icon(Icons.inbox_outlined),
+          selectedIcon: Icon(Icons.inbox),
+          label: 'Inbox',
+        ),
+      ];
+
+      expect(
+        () => tester.pumpWidget(
+          MaterialApp(
+            home: MediaQuery(
+              data: const MediaQueryData(size: Size(700, 900)),
+              child: AdaptiveScaffold(
+                destinations: destinations,
+              ),
+            ),
+          ),
+        ),
+        throwsA(isA<AssertionError>()),
+      );
+    },
+  );
 }
 
 /// An empty widget that implements [PreferredSizeWidget] to ensure that