api: Add translations for exceptions related to api requests

Also hook up some other test suites that require localization
contexts for tests to pass given this change.

Author: sirpengi

assets/l10n/app_en.arb

@@ -46,6 +46,24 @@
       "num": {"type": "int", "example": "4"}
     }
   },
+  "errorNetworkRequestFailed": "Network request failed",
+  "@errorNetworkRequestFailed": {
+    "description": "Error message when a network request fails."
+  },
+  "errorMalformedResponse": "Server gave malformed response; HTTP status {httpStatus}",
+  "@errorMalformedResponse": {
+    "description": "Error message when an API call fails because we could not parse it.",
+    "placeholders": {
+      "httpStatus": {"type": "int", "example": "200"}
+    }
+  },
+  "errorRequestFailed": "Network request failed: HTTP status {httpStatus}",
+  "@errorRequestFailed": {
+    "description": "Error message when an API call fails.",
+    "placeholders": {
+      "httpStatus": {"type": "int", "example": "500"}
+    }
+  },
   "userRoleOwner": "Owner",
   "@userRoleOwner": {
     "description": "Label for UserRole.owner"

lib/api/core.dart

@@ -4,6 +4,7 @@ import 'dart:io';
 import 'package:http/http.dart' as http;
 
 import '../log.dart';
+import '../model/localizations.dart';
 import 'exception.dart';
 
 /// A value for an API request parameter, to use directly without JSON encoding.
@@ -90,7 +91,8 @@ class ApiConnection {
       } else if (e is TlsException) {
         message = e.message;
       } else {
-        message = 'Network request failed';
+        final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
+        message = zulipLocalizations.errorNetworkRequestFailed;
       }
       throw NetworkException(routeName: routeName, cause: e, message: message);
     }

lib/api/exception.dart

@@ -1,4 +1,6 @@
 
+import '../model/localizations.dart';
+
 /// Some kind of error from a Zulip API network request.
 sealed class ApiRequestException implements Exception {
   /// The name of the Zulip API route for the request.
@@ -92,7 +94,8 @@ class Server5xxException extends ServerException {
     required super.httpStatus,
     required super.data,
   }) : assert(500 <= httpStatus && httpStatus <= 599),
-       super(message: 'Network request failed: HTTP status $httpStatus'); // TODO(i18n)
+       super(message: GlobalLocalizations.zulipLocalizations
+         .errorRequestFailed(httpStatus));
 }
 
 /// An error where the server's response doesn't match the Zulip API.
@@ -113,5 +116,6 @@ class MalformedServerResponseException extends ServerException {
     required super.routeName,
     required super.httpStatus,
     required super.data,
-  }) : super(message: 'Server gave malformed response; HTTP status $httpStatus'); // TODO(i18n)
+  }) : super(message: GlobalLocalizations.zulipLocalizations
+         .errorMalformedResponse(httpStatus));
 }

test/api/core_test.dart

@@ -3,6 +3,7 @@ import 'dart:io';
 
 import 'package:checks/checks.dart';
 import 'package:checks/context.dart';
+import 'package:flutter_gen/gen_l10n/zulip_localizations.dart';
 import 'package:http/http.dart' as http;
 import 'package:test/scaffolding.dart';
 import 'package:zulip/api/core.dart';
@@ -153,9 +154,11 @@ void main() {
           ..which(condition));
     }
 
+    final zulipLocalizations = lookupZulipLocalizations(ZulipLocalizations.supportedLocales.first);
     checkRequest(http.ClientException('Oops'), it()..message.equals('Oops'));
     checkRequest(const TlsException('Oops'), it()..message.equals('Oops'));
-    checkRequest((foo: 'bar'), it()..message.equals('Network request failed'));
+    checkRequest((foo: 'bar'), it()
+      ..message.equals(zulipLocalizations.errorNetworkRequestFailed));
   });
 
   test('API 4xx errors, well formed', () async {

test/widgets/autocomplete_test.dart

@@ -1,5 +1,6 @@
 import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/zulip_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/api/route/messages.dart';
@@ -40,6 +41,8 @@ Future<Finder> setupToComposeInput(WidgetTester tester, {
 
   await tester.pumpWidget(
     MaterialApp(
+      localizationsDelegates: ZulipLocalizations.localizationsDelegates,
+      supportedLocales: ZulipLocalizations.supportedLocales,
       home: GlobalStoreWidget(
         child: PerAccountStoreWidget(
           accountId: eg.selfAccount.id,

test/widgets/content_test.dart

@@ -3,6 +3,7 @@ import 'dart:io';
 import 'package:checks/checks.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/zulip_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:url_launcher/url_launcher.dart';
 import 'package:zulip/api/core.dart';
@@ -68,6 +69,8 @@ void main() {
       addTearDown(testBinding.reset);
 
       await tester.pumpWidget(GlobalStoreWidget(child: MaterialApp(
+        localizationsDelegates: ZulipLocalizations.localizationsDelegates,
+        supportedLocales: ZulipLocalizations.supportedLocales,
         home: PerAccountStoreWidget(accountId: eg.selfAccount.id,
           child: BlockContentList(
             nodes: parseContent(html).nodes)))));