release_schedule/test/view/movie_list_test.dart

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:release_schedule/model/dates.dart';
import 'package:release_schedule/model/movie.dart';
import 'package:release_schedule/view/movie_item.dart';
import 'package:release_schedule/view/movie_list.dart';

void main() {
  group('MovieList', () {
    testWidgets('should render a list of movies', (WidgetTester tester) async {
      final movies = [
        MovieData(
          'The Shawshank Redemption',
          DateWithPrecisionAndCountry(
              DateTime(1994, 9, 22), DatePrecision.day, 'US'),
        ),
        MovieData(
          'The Godfather',
          DateWithPrecisionAndCountry(
              DateTime(1972, 3, 24), DatePrecision.day, 'US'),
        ),
      ];

      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            body: MovieList(movies),
          ),
        ),
      );

      await tester.pumpAndSettle();

      expect(find.byType(MovieItem), findsNWidgets(movies.length));
    });

    testWidgets("should filter the list of movies",
        (WidgetTester tester) async {
      final movies = [
        MovieData(
          'The Shawshank Redemption',
          DateWithPrecisionAndCountry(
              DateTime(1994, 9, 22), DatePrecision.day, 'US'),
        ),
        MovieData(
          'The Godfather',
          DateWithPrecisionAndCountry(
              DateTime(1972, 3, 24), DatePrecision.day, 'US'),
        ),
      ];

      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            body: MovieList(
              movies,
              filter: (movie) => movie.title.contains('Godfather'),
            ),
          ),
        ),
      );

      await tester.pumpAndSettle();

      expect(find.byType(MovieItem), findsOneWidget);
    });
  });
}