diff --git a/das_client/test/model/journey/base_data_extension_test.dart b/das_client/test/model/journey/base_data_extension_test.dart
new file mode 100644
index 00000000..3bacd009
--- /dev/null
+++ b/das_client/test/model/journey/base_data_extension_test.dart
@@ -0,0 +1,104 @@
+import 'package:das_client/app/model/train_journey_settings.dart';
+import 'package:das_client/model/journey/balise.dart';
+import 'package:das_client/model/journey/balise_level_crossing_group.dart';
+import 'package:das_client/model/journey/base_data.dart';
+import 'package:das_client/model/journey/base_data_extension.dart';
+import 'package:das_client/model/journey/level_crossing.dart';
+import 'package:das_client/model/journey/whistles.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('Test balise and level crossing grouping', () {
+    final originalRows = <BaseData>[
+      Balise(order: 100, kilometre: [0.1], amountLevelCrossings: 1),
+      LevelCrossing(order: 101, kilometre: [0.11]),
+      Balise(order: 200, kilometre: [0.2], amountLevelCrossings: 1),
+      LevelCrossing(order: 202, kilometre: [0.22]),
+    ];
+
+    final notExpandedSettings = TrainJourneySettings();
+    final groupedRowsNotExpanded = originalRows.groupBaliseAndLeveLCrossings(notExpandedSettings);
+
+    expect(groupedRowsNotExpanded, hasLength(1));
+    expect(groupedRowsNotExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(4));
+
+    final expandedSettings = TrainJourneySettings(expandedGroups: [100]);
+    final groupedRowsExpanded = originalRows.groupBaliseAndLeveLCrossings(expandedSettings);
+
+    expect(groupedRowsExpanded, hasLength(5));
+    expect(groupedRowsExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(4));
+    expect(groupedRowsExpanded[1], isA<Balise>());
+    expect(groupedRowsExpanded[2], isA<LevelCrossing>());
+    expect(groupedRowsExpanded[3], isA<Balise>());
+    expect(groupedRowsExpanded[4], isA<LevelCrossing>());
+  });
+
+  test('Test balise and level crossing grouping with different amounts', () {
+    final originalRows = <BaseData>[
+      Balise(order: 100, kilometre: [0.1], amountLevelCrossings: 1),
+      LevelCrossing(order: 101, kilometre: [0.11]),
+      Balise(order: 200, kilometre: [0.2], amountLevelCrossings: 2),
+      LevelCrossing(order: 202, kilometre: [0.22]),
+      LevelCrossing(order: 203, kilometre: [0.23]),
+    ];
+
+    final notExpandedSettings = TrainJourneySettings();
+    final groupedRowsNotExpanded = originalRows.groupBaliseAndLeveLCrossings(notExpandedSettings);
+
+    expect(groupedRowsNotExpanded, hasLength(2));
+    expect(groupedRowsNotExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(2));
+    expect(groupedRowsNotExpanded[1], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[1] as BaliseLevelCrossingGroup).groupedElements, hasLength(3));
+
+    final expandedSettings = TrainJourneySettings(expandedGroups: [200]);
+    final groupedRowsExpanded = originalRows.groupBaliseAndLeveLCrossings(expandedSettings);
+
+    expect(groupedRowsExpanded, hasLength(5));
+    expect(groupedRowsExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(2));
+    expect(groupedRowsExpanded[1], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsExpanded[1] as BaliseLevelCrossingGroup).groupedElements, hasLength(3));
+    expect(groupedRowsExpanded[2], isA<Balise>());
+    expect(groupedRowsExpanded[3], isA<LevelCrossing>());
+    expect(groupedRowsExpanded[4], isA<LevelCrossing>());
+  });
+
+
+  test('Test balise and level crossing grouping with elements between', () {
+    final originalRows = <BaseData>[
+      Balise(order: 100, kilometre: [0.1], amountLevelCrossings: 1),
+      LevelCrossing(order: 101, kilometre: [0.11]),
+      Whistle(order: 155, kilometre: [0.22]),
+      Balise(order: 200, kilometre: [0.2], amountLevelCrossings: 1),
+      LevelCrossing(order: 202, kilometre: [0.22]),
+    ];
+
+    final notExpandedSettings = TrainJourneySettings();
+    final groupedRowsNotExpanded = originalRows.groupBaliseAndLeveLCrossings(notExpandedSettings);
+
+    expect(groupedRowsNotExpanded, hasLength(3));
+    expect(groupedRowsNotExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(2));
+    expect(groupedRowsNotExpanded[1], isA<Whistle>());
+    expect(groupedRowsNotExpanded[2], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[2] as BaliseLevelCrossingGroup).groupedElements, hasLength(2));
+  });
+
+  test('Test level crossing grouping', () {
+    final originalRows = <BaseData>[
+      LevelCrossing(order: 101, kilometre: [0.11]),
+      LevelCrossing(order: 202, kilometre: [0.22]),
+      LevelCrossing(order: 303, kilometre: [0.33]),
+    ];
+
+    final notExpandedSettings = TrainJourneySettings();
+    final groupedRowsNotExpanded = originalRows.groupBaliseAndLeveLCrossings(notExpandedSettings);
+
+    expect(groupedRowsNotExpanded, hasLength(1));
+    expect(groupedRowsNotExpanded[0], isA<BaliseLevelCrossingGroup>());
+    expect((groupedRowsNotExpanded[0] as BaliseLevelCrossingGroup).groupedElements, hasLength(3));
+  });
+}