zulip_binding: testable version of DateTime.now

lib/model/binding.dart

@@ -118,6 +118,12 @@ abstract class ZulipBinding {
   /// Outside tests, this just calls the [Stopwatch] constructor.
   Stopwatch stopwatch();
 
+  /// Provides access to current time.
+  ///
+  /// Please refer to this issue:
+  ///   https://github.com/dart-lang/sdk/issues/28985
+  DateTime now();
+
   /// Provides device and operating system information,
   /// via package:device_info_plus.
   ///
@@ -368,6 +374,9 @@ class LiveZulipBinding extends ZulipBinding {
   @override
   Stopwatch stopwatch() => Stopwatch();
 
+  @override
+  DateTime now() => DateTime.now();
+
   @override
   Future<BaseDeviceInfo?> get deviceInfo => _deviceInfo;
   late Future<BaseDeviceInfo?> _deviceInfo;

lib/model/store.dart

@@ -20,6 +20,7 @@ import '../api/route/realm.dart';
 import '../log.dart';
 import '../notifications/receive.dart';
 import 'autocomplete.dart';
+import 'binding.dart';
 import 'database.dart';
 import 'emoji.dart';
 import 'localizations.dart';
@@ -447,7 +448,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
   ///
   /// To determine if a user is a full member, callers must also check that the
   /// user's role is at least [UserRole.member].
-  bool hasPassedWaitingPeriod(User user, {required DateTime byDate}) {
+  bool hasPassedWaitingPeriod(User user) {
     // [User.dateJoined] is in UTC. For logged-in users, the format is:
     // YYYY-MM-DDTHH:mm+00:00, which includes the timezone offset for UTC.
     // For logged-out spectators, the format is: YYYY-MM-DD, which doesn't
@@ -459,7 +460,8 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
     // See the related discussion:
     //   https://chat.zulip.org/#narrow/channel/412-api-documentation/topic/provide.20an.20explicit.20format.20for.20.60realm_user.2Edate_joined.60/near/1980194
     final dateJoined = DateTime.parse(user.dateJoined);
-    return byDate.difference(dateJoined).inDays >= realmWaitingPeriodThreshold;
+    final now = ZulipBinding.instance.now();
+    return now.difference(dateJoined).inDays >= realmWaitingPeriodThreshold;
   }
 
   ////////////////////////////////
@@ -483,7 +485,6 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
   bool hasPostingPermission({
     required ZulipStream inChannel,
     required User user,
-    required DateTime byDate,
   }) {
     final role = user.role;
     // We let the users with [unknown] role to send the message, then the server
@@ -495,7 +496,7 @@ class PerAccountStore extends ChangeNotifier with EmojiStore, ChannelStore, Mess
       case ChannelPostPolicy.fullMembers:     {
         if (!role.isAtLeast(UserRole.member)) return false;
         return role == UserRole.member
-          ? hasPassedWaitingPeriod(user, byDate: byDate)
+          ? hasPassedWaitingPeriod(user)
           : true;
       }
       case ChannelPostPolicy.moderators:      return role.isAtLeast(UserRole.moderator);

lib/widgets/compose_box.dart

@@ -1410,8 +1410,7 @@ class _ComposeBoxState extends State<ComposeBox> with PerAccountStoreAwareStateM
       case ChannelNarrow(:final streamId):
       case TopicNarrow(:final streamId):
         final channel = store.streams[streamId];
-        if (channel == null || !store.hasPostingPermission(inChannel: channel,
-            user: selfUser, byDate: DateTime.now())) {
+        if (channel == null || !store.hasPostingPermission(inChannel: channel, user: selfUser)) {
           return _ErrorBanner(label:
             ZulipLocalizations.of(context).errorBannerCannotPostInChannelLabel);
         }

lib/widgets/message_list.dart

@@ -7,6 +7,7 @@ import 'package:intl/intl.dart' hide TextDirection;
 
 import '../api/model/model.dart';
 import '../generated/l10n/zulip_localizations.dart';
+import '../model/binding.dart';
 import '../model/message_list.dart';
 import '../model/narrow.dart';
 import '../model/store.dart';
@@ -1271,19 +1272,19 @@ class DateText extends StatelessWidget {
       ),
       formatHeaderDate(
         zulipLocalizations,
-        DateTime.fromMillisecondsSinceEpoch(timestamp * 1000),
-        now: DateTime.now()));
+        DateTime.fromMillisecondsSinceEpoch(timestamp * 1000)));
   }
 }
 
 @visibleForTesting
 String formatHeaderDate(
   ZulipLocalizations zulipLocalizations,
-  DateTime dateTime, {
-  required DateTime now,
-}) {
-  assert(!dateTime.isUtc && !now.isUtc,
-    '`dateTime` and `now` need to be in local time.');
+  DateTime dateTime,
+) {
+  assert(!dateTime.isUtc,
+    '`dateTime` need to be in local time.');
+
+  final now = ZulipBinding.instance.now();
 
   if (dateTime.year == now.year &&
       dateTime.month == now.month &&

test/model/binding.dart

@@ -214,6 +214,9 @@ class TestZulipBinding extends ZulipBinding {
   @override
   Stopwatch stopwatch() => clock.stopwatch();
 
+  @override
+  DateTime now() => clock.now();
+
   /// The value that `ZulipBinding.instance.deviceInfo` should return.
   BaseDeviceInfo deviceInfoResult = _defaultDeviceInfoResult;
   static const _defaultDeviceInfoResult = AndroidDeviceInfo(sdkInt: 33, release: '13');

test/model/store_test.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:io';
 
 import 'package:checks/checks.dart';
+import 'package:clock/clock.dart';
 import 'package:fake_async/fake_async.dart';
 import 'package:flutter/foundation.dart';
 import 'package:http/http.dart' as http;
@@ -260,9 +261,11 @@ void main() {
     for (final (String dateJoined, DateTime currentDate, bool hasPassedWaitingPeriod) in testCases) {
       test('user joined at $dateJoined ${hasPassedWaitingPeriod ? 'has' : "hasn't"} '
           'passed waiting period by $currentDate', () {
-        final user = eg.user(dateJoined: dateJoined);
-        check(store.hasPassedWaitingPeriod(user, byDate: currentDate))
-          .equals(hasPassedWaitingPeriod);
+        withClock(Clock.fixed(currentDate), () {
+          final user = eg.user(dateJoined: dateJoined);
+          check(store.hasPassedWaitingPeriod(user))
+            .equals(hasPassedWaitingPeriod);
+        });
       });
     }
   });
@@ -306,11 +309,10 @@ void main() {
       test('"${role.name}" user ${canPost ? 'can' : "can't"} post in channel '
           'with "${policy.name}" policy', () {
         final store = eg.store();
+        // we don't use `withClock` because current time is not actually relevant for
+        // these test cases; for the ones which it is, they're practiced below.
         final actual = store.hasPostingPermission(
-          inChannel: eg.stream(channelPostPolicy: policy), user: eg.user(role: role),
-          // [byDate] is not actually relevant for these test cases; for the
-          // ones which it is, they're practiced below.
-          byDate: DateTime.now());
+          inChannel: eg.stream(channelPostPolicy: policy), user: eg.user(role: role));
         check(actual).equals(canPost);
       });
     }
@@ -324,21 +326,23 @@ void main() {
         role: UserRole.member, dateJoined: dateJoined);
 
       test('a "full" member -> can post in the channel', () {
-        final store = localStore(realmWaitingPeriodThreshold: 3);
-        final hasPermission = store.hasPostingPermission(
-          inChannel: eg.stream(channelPostPolicy: ChannelPostPolicy.fullMembers),
-          user: memberUser(dateJoined: '2024-11-25T10:00+00:00'),
-          byDate: DateTime.utc(2024, 11, 28, 10, 00));
-        check(hasPermission).isTrue();
+        withClock(Clock.fixed(DateTime.utc(2024, 11, 28, 10, 00)), () {
+          final store = localStore(realmWaitingPeriodThreshold: 3);
+          final hasPermission = store.hasPostingPermission(
+            inChannel: eg.stream(channelPostPolicy: ChannelPostPolicy.fullMembers),
+            user: memberUser(dateJoined: '2024-11-25T10:00+00:00'));
+          check(hasPermission).isTrue();
+        });
       });
 
       test('not a "full" member -> cannot post in the channel', () {
-        final store = localStore(realmWaitingPeriodThreshold: 3);
-        final actual = store.hasPostingPermission(
-          inChannel: eg.stream(channelPostPolicy: ChannelPostPolicy.fullMembers),
-          user: memberUser(dateJoined: '2024-11-25T10:00+00:00'),
-          byDate: DateTime.utc(2024, 11, 28, 09, 59));
-        check(actual).isFalse();
+        withClock(Clock.fixed(DateTime.utc(2024, 11, 28, 09, 59)), () {
+          final store = localStore(realmWaitingPeriodThreshold: 3);
+          final actual = store.hasPostingPermission(
+            inChannel: eg.stream(channelPostPolicy: ChannelPostPolicy.fullMembers),
+            user: memberUser(dateJoined: '2024-11-25T10:00+00:00'));
+          check(actual).isFalse();
+        });
       });
     });
   });

test/widgets/message_list_test.dart

@@ -1,6 +1,7 @@
 import 'dart:convert';
 
 import 'package:checks/checks.dart';
+import 'package:clock/clock.dart';
 import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
@@ -1107,7 +1108,7 @@ void main() {
         .initNarrow.equals(DmNarrow.withUser(eg.otherUser.userId, selfUserId: eg.selfUser.userId));
       await tester.pumpAndSettle();
     });
-    
+
     testWidgets('does not navigate on tapping recipient header in DmNarrow', (tester) async {
       final pushedRoutes = <Route<void>>[];
       final navObserver = TestNavigatorObserver()
@@ -1129,7 +1130,6 @@ void main() {
 
   group('formatHeaderDate', () {
     final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
-    final now = DateTime.parse("2023-01-10 12:00");
     final testCases = [
       ("2023-01-10 12:00", zulipLocalizations.today),
       ("2023-01-10 00:00", zulipLocalizations.today),
@@ -1144,8 +1144,10 @@ void main() {
     ];
     for (final (dateTime, expected) in testCases) {
       test('$dateTime returns $expected', () {
-        check(formatHeaderDate(zulipLocalizations, DateTime.parse(dateTime), now: now))
-          .equals(expected);
+        withClock(Clock.fixed(DateTime.parse("2023-01-10 12:00")), () {
+          check(formatHeaderDate(zulipLocalizations, DateTime.parse(dateTime)))
+            .equals(expected);
+        });
       });
     }
   });