Replace randomness in tests with deterministic randomness. (#1320)

This PR makes tests that use randomness deterministic. This is done by
using the `TEST_RANDOMNESS_SEED` environment variable that is passed to
Dart by the `sz test` command. This seed will be used for generating
randomness, so that we can reuse a seed that made a test fail in e.g. a
CI pipeline.

I replaced all instances of randomness from `package:random_string` with
a new custom package called `test_randomness`.
This package also includes a seeded `Random` called `szTestRandom` that
should be used in all future tests.

Requires #1318 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Introduced a new library for generating random values for testing
purposes, enhancing the ability to produce diverse test scenarios.
- Added an option to randomize test case execution order, allowing for
more robust test coverage.

- **Tests**
- Updated various test files across the application to utilize the new
`test_randomness` library for generating random numbers and strings,
improving test reliability and predictability.

- **Chores**
- Implemented comprehensive `.gitignore` rules for a wide range of
development environments, ensuring a cleaner repository.

- **Documentation**
- Added metadata tracking for project properties in the
`test_randomness` library, ensuring better project management and
version control.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/pubspec.yaml

@@ -215,7 +215,8 @@ dev_dependencies:
   integration_test:
     sdk: flutter
   mockito: ^5.4.4
-  random_string: ^2.0.1
+  test_randomness:
+    path: ../lib/test_randomness
   bloc_test: ^9.1.4
   bloc_presentation_test: ^1.0.0
   path: ^1.8.3

app/test/dashboard/update_reminder_bloc_test.dart

@@ -6,12 +6,11 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
-import 'dart:math';
-
 import 'package:flutter_test/flutter_test.dart';
+import 'package:sharezone/changelog/change.dart';
 import 'package:sharezone/dashboard/update_reminder/release.dart';
 import 'package:sharezone/dashboard/update_reminder/update_reminder_bloc.dart';
-import 'package:sharezone/changelog/change.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 void main() {
   group('UpdateReminderBloc', () {
@@ -140,5 +139,5 @@ Release _releaseWith({required String version, DateTime? releaseTime}) {
   return Release(
       version: Version.parse(name: version),
       releaseDate:
-          releaseTime ?? DateTime(2020, 02, Random.secure().nextInt(25) + 1));
+          releaseTime ?? DateTime(2020, 02, szTestRandom.nextInt(25) + 1));
 }

app/test/feedback/feedback_bloc_test.dart

@@ -9,12 +9,12 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:key_value_store/key_value_store.dart';
-import 'package:random_string/random_string.dart' as random;
 import 'package:sharezone/feedback/src/analytics/feedback_analytics.dart';
 import 'package:sharezone/feedback/src/bloc/feedback_bloc.dart';
 import 'package:sharezone/feedback/src/cache/cooldown_exception.dart';
 import 'package:sharezone/feedback/src/cache/feedback_cache.dart';
 import 'package:sharezone/feedback/src/models/user_feedback.dart';
+import 'package:test_randomness/test_randomness.dart' as random;
 
 import 'mock_feedback_api.dart';
 import 'mock_platform_information_retreiver.dart';

app/test/feedback/feedback_page_test.dart

@@ -10,12 +10,12 @@ import 'package:bloc_provider/bloc_provider.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:key_value_store/in_memory_key_value_store.dart';
-import 'package:random_string/random_string.dart' as random;
 import 'package:sharezone/feedback/feedback_box_page.dart';
 import 'package:sharezone/feedback/src/bloc/feedback_bloc.dart';
 import 'package:sharezone/feedback/src/cache/cooldown_exception.dart';
 import 'package:sharezone/feedback/src/cache/feedback_cache.dart';
 import 'package:sharezone/feedback/src/models/user_feedback.dart';
+import 'package:test_randomness/test_randomness.dart' as random;
 
 import 'feedback_bloc_test.dart';
 import 'mock_feedback_api.dart';

app/test/groups/group_join_select_courses_bloc_test.dart

@@ -13,12 +13,12 @@ import 'package:design/design.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:group_domain_models/group_domain_models.dart';
 import 'package:mockito/annotations.dart';
-import 'package:random_string/random_string.dart';
 import 'package:sharezone/groups/group_join/bloc/group_join_bloc.dart';
 import 'package:sharezone/groups/group_join/bloc/group_join_select_courses_bloc.dart';
 import 'package:sharezone/groups/group_join/models/group_info_with_selection_state.dart';
 import 'package:sharezone/groups/group_join/models/group_join_result.dart';
 import 'package:sharezone/util/api/connections_gateway.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 import 'group_join_select_courses_bloc_test.mocks.dart';
 

app/test/holidays/holiday_bloc_unit_test.dart

@@ -11,7 +11,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:holidays/holidays.dart';
 import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
-import 'package:random_string/random_string.dart' as rdm;
+import 'package:test_randomness/test_randomness.dart' as rdm;
 import 'package:rxdart/subjects.dart';
 import 'package:sharezone/holidays/holiday_bloc.dart';
 import 'package:user/user.dart';

app/test/homework/homework_dialog_test.dart

@@ -25,7 +25,7 @@ import 'package:group_domain_models/group_domain_models.dart';
 import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
 import 'package:path/path.dart';
-import 'package:random_string/random_string.dart';
+import 'package:test_randomness/test_randomness.dart';
 import 'package:sharezone/homework/homework_dialog/homework_dialog.dart';
 import 'package:sharezone/homework/homework_dialog/homework_dialog_bloc.dart';
 import 'package:sharezone/main/application_bloc.dart';

app/test/homework/teacher/teacher_homework_page_widget_test.dart

@@ -13,20 +13,20 @@ import 'package:analytics/null_analytics_backend.dart';
 import 'package:bloc_provider/bloc_provider.dart';
 import 'package:bloc_provider/multi_bloc_provider.dart';
 import 'package:common_domain_models/common_domain_models.dart';
-import 'package:flutter/material.dart' hide Color;
 import 'package:flutter/material.dart' as flutter show Color;
+import 'package:flutter/material.dart' hide Color;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:hausaufgabenheft_logik/color.dart';
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik_lehrer.dart';
 import 'package:provider/provider.dart';
-import 'package:random_string/random_string.dart';
 import 'package:sharezone/homework/shared/shared.dart';
 import 'package:sharezone/homework/teacher/src/teacher_archived_homework_list.dart';
 import 'package:sharezone/homework/teacher/src/teacher_homework_bottom_action_bar.dart';
 import 'package:sharezone/homework/teacher/src/teacher_homework_tile.dart';
 import 'package:sharezone/homework/teacher/src/teacher_open_homework_list.dart';
 import 'package:sharezone/homework/teacher/teacher_homework_page.dart';
 import 'package:sharezone/navigation/logic/navigation_bloc.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 class MockTeacherHomeworkPageBloc extends TeacherHomeworkPageBloc {
   final _queuedStates = Queue<TeacherHomeworkPageState>();

app/test/timetable/school_class_filter_view_test.dart

@@ -8,9 +8,8 @@
 
 import 'package:common_domain_models/common_domain_models.dart';
 import 'package:flutter_test/flutter_test.dart';
-
-import 'package:random_string/random_string.dart';
 import 'package:sharezone/timetable/timetable_page/school_class_filter/school_class_filter_view.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 void main() {
   group('SchoolClassFilterView', () {

app/test/timetable/timetable_bloc_test.dart

@@ -6,8 +6,6 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
-import 'dart:math';
-
 import 'package:clock/clock.dart';
 import 'package:common_domain_models/common_domain_models.dart';
 import 'package:date/src/date.dart';
@@ -19,6 +17,7 @@ import 'package:sharezone/calendrical_events/models/calendrical_event.dart';
 import 'package:sharezone/timetable/src/bloc/timetable_bloc.dart';
 import 'package:sharezone/timetable/src/models/lesson.dart';
 import 'package:sharezone/timetable/timetable_page/school_class_filter/school_class_filter_view.dart';
+import 'package:test_randomness/test_randomness.dart';
 import 'package:time/time.dart';
 
 import 'mock/mock_course_gateway.dart';
@@ -50,7 +49,7 @@ void main() {
         endTime: Time(hour: 10, minute: 0),
         groupID: groupId,
         groupType: GroupType.course,
-        lessonID: Random().nextInt(200).toString(),
+        lessonID: szTestRandom.nextInt(200).toString(),
         place: "",
         teacher: "",
         weekday: WeekDay.monday,

lib/abgabe/abgabe_client_lib/pubspec.yaml

@@ -46,6 +46,7 @@ dev_dependencies:
     sdk: flutter
   async: ^2.4.1
   mockito: ^5.4.4
-  random_string: ^2.0.1
+  test_randomness:
+    path: ../../test_randomness
   sharezone_lints:
     path: ../../sharezone_lints

lib/abgabe/abgabe_client_lib/test/bloc_test.dart

@@ -25,8 +25,8 @@ import 'package:common_domain_models/common_domain_models.dart';
 import 'package:files_basics/files_models.dart';
 import 'package:files_basics/local_file.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:random_string/random_string.dart';
 import 'package:rxdart/subjects.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 void main() {
   group(

lib/hausaufgabenheft_logik/lib/src/lehrer/teacher_homework_page_bloc.dart

@@ -14,7 +14,7 @@ import 'package:common_domain_models/common_domain_models.dart';
 import 'package:hausaufgabenheft_logik/color.dart';
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik_lehrer.dart';
 import 'package:meta/meta.dart';
-import 'package:random_string/random_string.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 export 'events.dart';
 export 'states.dart';

lib/hausaufgabenheft_logik/pubspec.yaml

@@ -28,7 +28,8 @@ dependencies:
     path: ../bloc_base
   # For teacher fake bloc currently in use (can be removed when bloc is implemented)
   # https://gitlab.com/codingbrain/sharezone/sharezone-app/-/issues/1460
-  random_string: ^2.0.1
+  test_randomness:
+    path: ../test_randomness
   clock: ^1.1.1
 
 dev_dependencies:

lib/hausaufgabenheft_logik/test/create_homework_util.dart

@@ -6,12 +6,11 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
-import 'dart:math';
-
 import 'package:common_domain_models/common_domain_models.dart';
 import 'package:hausaufgabenheft_logik/src/models/homework/homework.dart';
 import 'package:hausaufgabenheft_logik/src/models/homework/models_used_by_homework.dart';
 import 'package:hausaufgabenheft_logik/src/views/color.dart';
+import 'package:test_randomness/test_randomness.dart';
 
 HomeworkReadModel createHomework(
     {Date todoDate = const Date(day: 1, month: 1, year: 2019),
@@ -22,7 +21,7 @@ HomeworkReadModel createHomework(
     bool withSubmissions = false,
     Color? subjectColor,
     String abbreviation = 'Abb'}) {
-  id = id == 'willBeRandom' ? randomString(5) : id;
+  id = id == 'willBeRandom' ? randomAlphaNumeric(5) : id;
   return HomeworkReadModel(
     id: HomeworkId(id),
     todoDate: todoDate.asDateTime(),
@@ -32,12 +31,3 @@ HomeworkReadModel createHomework(
     status: done ? CompletionStatus.completed : CompletionStatus.open,
   );
 }
-
-String randomString(int length) {
-  var rand = Random();
-  var codeUnits = List.generate(length, (index) {
-    return rand.nextInt(33) + 89;
-  });
-
-  return String.fromCharCodes(codeUnits);
-}