Add tests

Author: NRijnberg

test/pagination/pagination_mixin_test.dart

@@ -0,0 +1,100 @@
+// Ignored because its more descriptive to specify the arguments in the test.
+// Immutable warning is ignored for testing purposes.
+//ignore_for_file: avoid_redundant_argument_values, avoid_equals_and_hash_code_on_mutable_classes
+import 'package:dcc_toolkit/pagination/pagination_interface.dart';
+import 'package:dcc_toolkit/pagination/pagination_mixin.dart';
+import 'package:dcc_toolkit/pagination/pagination_state.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:parameterized_test/parameterized_test.dart';
+
+void main() {
+  group('pagination_state tests', () {
+    parameterizedTest(
+      'hasNextPage',
+      [
+        [1, 1, false],
+        [2, 2, false],
+        [2, 1, false],
+        [1, -1, false],
+        [-1, 1, true],
+        [1, 2, true],
+      ],
+      (int currentPage, int lastPage, bool expected) =>
+          expect(PaginationState<int>(items: [], currentPage: currentPage, lastPage: lastPage).hasNextPage, expected),
+    );
+  });
+
+  group('PaginationMixin tests', () {
+    late _TestCubit cubit;
+
+    setUp(() {
+      cubit = _TestCubit();
+    });
+
+    test('loadNextPage emits new state with next page items when current page is less than last page', () async {
+      final paginationState = PaginationState<int>(items: [1, 2, 3], currentPage: 1, lastPage: 3);
+      cubit.emit(_TestState(paginationState));
+
+      final nextPaginationStates = <PaginationState<int>?>[];
+      await cubit.loadNextPage(nextPaginationStates.add);
+
+      expect(nextPaginationStates.first!.isLoading, isTrue);
+      expect(nextPaginationStates.length, 2);
+      expect(nextPaginationStates.last!.items, equals([1, 2, 3, 1, 2, 3]));
+      expect(nextPaginationStates.last!.currentPage, equals(2));
+      expect(nextPaginationStates.last!.isLoading, isFalse);
+    });
+
+    test('loadNextPage does not emit new state when current page is equal to last page', () async {
+      final paginationState = PaginationState<int>(items: [1, 2, 3], currentPage: 3, lastPage: 3);
+      cubit.emit(_TestState(paginationState));
+
+      final nextPaginationStates = <PaginationState<int>?>[];
+      await cubit.loadNextPage(nextPaginationStates.add);
+
+      expect(nextPaginationStates, isEmpty);
+    });
+
+    test('loadNextPage does not emit new state when next page items are empty', () async {
+      final paginationState = PaginationState<int>(items: [1, 2, 3], currentPage: 1, lastPage: 3);
+      cubit
+        ..emit(_TestState(paginationState))
+        ..returnPages = [];
+
+      final nextPaginationStates = <PaginationState<int>?>[];
+      await cubit.loadNextPage(nextPaginationStates.add);
+
+      expect(nextPaginationStates.first!.isLoading, isTrue);
+      expect(nextPaginationStates.length, 1);
+    });
+  });
+}
+
+class _TestState implements PaginationInterface<int> {
+  _TestState(this.paginationState);
+
+  @override
+  final PaginationState<int> paginationState;
+
+  @override
+  int get hashCode => paginationState.hashCode;
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    return other is _TestState && other.paginationState == paginationState;
+  }
+}
+
+class _TestCubit extends Cubit<_TestState> with PaginationMixin<int, _TestState> {
+  _TestCubit() : super(_TestState(PaginationState()));
+
+  List<int> returnPages = [1, 2, 3];
+
+  @override
+  Future<List<int>?> fetchPageItems({required int page, String? searchQuery}) async => returnPages;
+
+  @override
+  Future<void> initializeState({String? searchQuery}) async {}
+}