wip api start on tests for notif parsing

test/api/notifications_test.dart

@@ -0,0 +1,84 @@
+import 'package:checks/checks.dart';
+import 'package:test/scaffolding.dart';
+import 'package:zulip/api/notifications.dart';
+
+void main() {
+  final baseBaseJson = {
+    "server": "zulip.example.cloud",  // corresponds to EXTERNAL_HOST
+    "realm_id": "4",
+    "realm_uri": "https://zulip.example.com",  // corresponds to realm.uri
+    "user_id": "234",
+  };
+
+  group('FcmMessage', () {
+    test('parse fails on missing or bad event type', () {
+      check(FcmMessage.fromJson({})).isA<UnexpectedFcmMessage>();
+      check(FcmMessage.fromJson({'event': 'nonsense'})).isA<UnexpectedFcmMessage>();
+    });
+  });
+
+  // TODO adapt RecipientTest
+
+  group('MessageFcmMessage', () {
+    final baseJson = {
+      ...baseBaseJson,
+      "event": "message",
+
+      "zulip_message_id": "12345",
+
+      "sender_id": "123",
+      "sender_email": "[email protected]",
+      "sender_avatar_url": "https://zulip.example.com/avatar/123.jpeg",
+      "sender_full_name": "A Sender",
+
+      "time": "1546300800",  // a Unix seconds-since-epoch
+
+      "content": "This is a message",  // rendered_content, reduced to plain text
+      "content_truncated": "This is a m…",
+    };
+
+    final streamJson = {
+      ...baseJson,
+      "recipient_type": "stream",
+      "stream_id": "42",
+      "stream": "denmark",
+      "topic": "play",
+
+      "alert": "New stream message from A Sender in denmark",
+    };
+
+    final groupDmJson = {
+      ...baseJson,
+      "recipient_type": "private",
+      "pm_users": "123,234,345",
+
+      "alert": "New private group message from A Sender",
+    };
+
+    final dmJson = {
+      ...baseJson,
+      "recipient_type": "private",
+
+      "alert": "New private message from A Sender",
+    };
+
+    test("'message' messages parse as MessageFcmMessage", () {
+      check(FcmMessage.fromJson(streamJson)).isA<MessageFcmMessage>();
+    });
+
+    MessageFcmMessage parse(Map<String, dynamic> json) {
+      return FcmMessage.fromJson(json) as MessageFcmMessage;
+    }
+
+    test("fields get parsed right in 'message' happy path", () {
+      final streamParsed = parse(streamJson);
+      check(streamParsed.server).equals(baseJson['server']!);
+      check(streamParsed.realmId).equals(4);
+      check(streamParsed.realmUri).equals(Uri.parse(baseJson['realm_uri']!));
+      check(streamParsed.userId).equals(234);
+      // TODO more here
+    });
+  });
+
+  // TODO adapt remaining test cases from zulip-mobile:android/app/src/test/java/com/zulipmobile/notifications/FcmMessageTest.kt
+}