diff --git a/example/lib/example_expansion.dart b/example/lib/example_expansion.dart
new file mode 100644
index 0000000..1a2e288
--- /dev/null
+++ b/example/lib/example_expansion.dart
@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+import 'package:searchable_listview/searchable_listview.dart';
+
+class ExampleExpansion extends StatelessWidget {
+  const ExampleExpansion({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: SearchableList.expansion(
+        expansionListData: const {},
+        expansionTitleBuilder: (context) {
+          return const Text('Example Expansion');
+        },
+        filterExpansionData: filterFunction,
+        expansionListBuilder: (_, __) {
+          return const Text('Example Expansion Item');
+        },
+      ),
+    );
+  }
+
+  Map<dynamic, List<dynamic>> filterFunction(String filter) {
+    return {};
+  }
+}
diff --git a/lib/searchable_listview.dart b/lib/searchable_listview.dart
index 86845e6..588c970 100644
--- a/lib/searchable_listview.dart
+++ b/lib/searchable_listview.dart
@@ -271,7 +271,7 @@ class SearchableList<T> extends StatefulWidget {
   /// Callback invoked when filtring the searchable list
   /// used when providing [asyncListCallback]
   /// can't be null when [asyncListCallback] isn't null
-  late List<T> Function(String, List<T>)? asyncListFilter;
+  late List<T> Function(String query, List<T> list)? asyncListFilter;
 
   /// Loading widget displayed when [asyncListCallback] is loading
   /// if nothing is provided in [loadingWidget] searchable list will display a [CircularProgressIndicator]
@@ -316,7 +316,7 @@ class SearchableList<T> extends StatefulWidget {
   final TextInputType textInputType;
 
   /// Callback function invoked when submiting the search text field
-  final Function(String?)? onSubmitSearch;
+  final Function(String? search)? onSubmitSearch;
 
   /// The search type on submiting text field or when changing the text field value
   /// ```dart
@@ -409,11 +409,11 @@ class SearchableList<T> extends StatefulWidget {
 
   /// Callback used when filtering the expansion list
   /// required when using [expansion] constructor
-  late Map<dynamic, List<T>> Function(String)? filterExpansionData;
+  late Map<dynamic, List<T>> Function(String query)? filterExpansionData;
 
   /// The expansion list title widget builder
   /// required when using [expansion] constructor
-  late Widget Function(dynamic) expansionTitleBuilder;
+  late Widget Function(dynamic header) expansionTitleBuilder;
 
   /// Physics attributes used in listview widget
   late ScrollPhysics? physics;
diff --git a/test/expansion_searchable_listview_test.dart b/test/expansion_searchable_listview_test.dart
new file mode 100644
index 0000000..1a4e89d
--- /dev/null
+++ b/test/expansion_searchable_listview_test.dart
@@ -0,0 +1,180 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:searchable_listview/searchable_listview.dart';
+
+void main() {
+  group('ExpansionSearchableListView Display', () {
+    testWidgets('''
+        Veryfing expansion searchable listview default display
+      ''', (test) async {
+      final dataMap = {
+        'Fruits': ['Apple', 'Banana', 'Orange'],
+        'Vegetables': ['Carrot', 'Broccoli', 'Spinach'],
+      };
+
+      final expansionListView = SearchableList<String>.expansion(
+        expansionListData: dataMap,
+        expansionListBuilder: (expansionGroupIndex, listItem) {
+          return ListTile(
+            title: Text(listItem),
+          );
+        },
+        expansionTitleBuilder: (header) {
+          return Text(header);
+        },
+        filterExpansionData: (_) {
+          return {};
+        },
+        initiallyExpanded: true,
+      );
+
+      await test.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: Center(
+              child: expansionListView,
+            ),
+          ),
+        ),
+      );
+
+      expect(find.text('Fruits'), findsOneWidget);
+      expect(find.text('Vegetables'), findsOneWidget);
+      expect(find.text('Apple'), findsOneWidget);
+      expect(find.text('Carrot'), findsOneWidget);
+
+      final searchField = find.byType(TextField);
+      await test.enterText(searchField, '2');
+      await test.pumpAndSettle();
+
+      expect(find.text('Apple'), findsNothing);
+    });
+
+    testWidgets('''
+        Veryfing expansion searchable listview display when not expanded
+      ''', (test) async {
+      final dataMap = {
+        'Fruits': ['Apple', 'Banana', 'Orange'],
+        'Vegetables': ['Carrot', 'Broccoli', 'Spinach'],
+      };
+
+      final expansionListView = SearchableList<String>.expansion(
+        expansionListData: dataMap,
+        expansionListBuilder: (expansionGroupIndex, listItem) {
+          return ListTile(
+            title: Text(listItem),
+          );
+        },
+        expansionTitleBuilder: (header) {
+          return Text(header);
+        },
+        filterExpansionData: (_) {
+          return {};
+        },
+      );
+
+      await test.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: Center(
+              child: expansionListView,
+            ),
+          ),
+        ),
+      );
+
+      expect(find.text('Fruits'), findsOneWidget);
+      expect(find.text('Vegetables'), findsOneWidget);
+      expect(find.text('Apple'), findsNothing);
+      expect(find.text('Carrot'), findsNothing);
+    });
+
+    testWidgets('''
+        Veryfing expansion searchable listview display and tap to expand
+      ''', (test) async {
+      final dataMap = {
+        'Fruits': ['Apple', 'Banana', 'Orange'],
+        'Vegetables': ['Carrot', 'Broccoli', 'Spinach'],
+      };
+
+      final expansionListView = SearchableList<String>.expansion(
+        expansionListData: dataMap,
+        expansionListBuilder: (expansionGroupIndex, listItem) {
+          return ListTile(
+            title: Text(listItem),
+          );
+        },
+        expansionTitleBuilder: (header) {
+          return Text(header);
+        },
+        filterExpansionData: (_) {
+          return {};
+        },
+      );
+
+      await test.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: Center(
+              child: expansionListView,
+            ),
+          ),
+        ),
+      );
+
+      expect(find.text('Fruits'), findsOneWidget);
+      expect(find.text('Vegetables'), findsOneWidget);
+
+      final fruitsHeader = find.text('Fruits');
+      await test.tap(fruitsHeader);
+      await test.pumpAndSettle();
+
+      expect(find.text('Apple'), findsOneWidget);
+    });
+
+    testWidgets('''
+        Veryifing empty widget display when search yields no results
+      ''', (test) async {
+      final dataMap = {
+        'Fruits': ['Apple', 'Banana', 'Orange'],
+        'Vegetables': ['Carrot', 'Broccoli', 'Spinach'],
+      };
+
+      final expansionListView = SearchableList<String>.expansion(
+        expansionListData: dataMap,
+        expansionListBuilder: (expansionGroupIndex, listItem) {
+          return ListTile(
+            title: Text(listItem),
+          );
+        },
+        expansionTitleBuilder: (header) {
+          return Text(header);
+        },
+        filterExpansionData: (_) {
+          return {};
+        },
+        emptyWidget: const Text('No items found'),
+      );
+
+      await test.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: Center(
+              child: expansionListView,
+            ),
+          ),
+        ),
+      );
+
+      expect(find.text('Fruits'), findsOneWidget);
+      expect(find.text('Vegetables'), findsOneWidget);
+
+      final searchField = find.byType(TextField);
+      await test.enterText(searchField, '2');
+      await test.pumpAndSettle();
+
+      expect(find.text('Apple'), findsNothing);
+      expect(find.text('No items found'), findsOneWidget);
+    });
+  });
+}