db: Add a migration, and a migration test

We didn't really need to do this as a migration, because we
already know we need this column and so we could have included it
from the start.  But this lets us exercise Drift's support for
migrations, and for testing migrations.

Author: gnprice

lib/model/database.dart

@@ -20,6 +20,8 @@ class Accounts extends Table {
   Column<String> get zulipMergeBase => text().nullable()();
   Column<int>    get zulipFeatureLevel => integer()();
 
+  Column<String> get ackedPushToken => text().nullable()();
+
   @override
   List<Set<Column<Object>>> get uniqueKeys => [
     {realmUrl, userId},
@@ -58,7 +60,7 @@ class AppDatabase extends _$AppDatabase {
   //  * Write tests.
   // TODO run those `drift_dev schema` commands in CI: https://github.com/zulip/zulip-flutter/issues/60
   @override
-  int get schemaVersion => 1; // See note.
+  int get schemaVersion => 2; // See note.
 
   @override
   MigrationStrategy get migration {
@@ -80,6 +82,11 @@ class AppDatabase extends _$AppDatabase {
           return;
         }
         assert(1 <= from && from <= to && to <= schemaVersion);
+
+        if (from < 2 && 2 <= to) {
+          await m.addColumn(accounts, accounts.ackedPushToken);
+        }
+        // New migrations go here.
       }
     );
   }

lib/model/database.g.dart

@@ -1,38 +1,87 @@
 import 'package:checks/checks.dart';
 import 'package:drift/drift.dart';
 import 'package:drift/native.dart';
+import 'package:drift_dev/api/migrations.dart';
 import 'package:test/scaffolding.dart';
 import 'package:zulip/model/database.dart';
 
+import 'schemas/schema.dart';
+import 'schemas/schema_v1.dart' as v1;
+import 'schemas/schema_v2.dart' as v2;
+
 void main() {
-  late AppDatabase database;
+  group('non-migration tests', () {
+    late AppDatabase database;
 
-  setUp(() {
-    database = AppDatabase(NativeDatabase.memory());
-  });
-  tearDown(() async {
-    await database.close();
+    setUp(() {
+      database = AppDatabase(NativeDatabase.memory());
+    });
+    tearDown(() async {
+      await database.close();
+    });
+
+    test('create account', () async {
+      final accountData = AccountsCompanion.insert(
+        realmUrl: Uri.parse('https://chat.example/'),
+        userId: 1,
+        email: '[email protected]',
+        apiKey: '1234',
+        zulipVersion: '6.0',
+        zulipMergeBase: const Value('6.0'),
+        zulipFeatureLevel: 42,
+      );
+      final accountId = await database.createAccount(accountData);
+      final account = await (database.select(database.accounts)
+            ..where((a) => a.id.equals(accountId)))
+          .watchSingle()
+          .first;
+      check(account.toCompanion(false).toJson()).deepEquals({
+        ...accountData.toJson(),
+        'id': it(),
+        'acked_push_token': null,
+      });
+    });
   });
 
-  test('create account', () async {
-    // TODO use example_data
-    final accountData = AccountsCompanion.insert(
-      realmUrl: Uri.parse('https://chat.example/'),
-      userId: 1,
-      email: '[email protected]',
-      apiKey: '1234',
-      zulipVersion: '6.0',
-      zulipMergeBase: const Value('6.0'),
-      zulipFeatureLevel: 42,
-    );
-    final accountId = await database.createAccount(accountData);
-    final account = await (database.select(database.accounts)
-          ..where((a) => a.id.equals(accountId)))
-        .watchSingle()
-        .first;
-    check(account.toCompanion(false).toJson()).deepEquals({
-      ...accountData.toJson(),
-      'id': it(),
+  group('migrations', () {
+    late SchemaVerifier verifier;
+
+    setUpAll(() {
+      verifier = SchemaVerifier(GeneratedHelper());
+    });
+
+    test('upgrade to v2, empty', () async {
+      final connection = await verifier.startAt(1);
+      final db = AppDatabase(connection);
+      await verifier.migrateAndValidate(db, 2);
+      await db.close();
+    });
+
+    test('upgrade to v2, with data', () async {
+      final schema = await verifier.schemaAt(1);
+      final before = v1.DatabaseAtV1(schema.newConnection());
+      await before.into(before.accounts).insert(v1.AccountsCompanion.insert(
+        realmUrl: 'https://chat.example/',
+        userId: 1,
+        email: '[email protected]',
+        apiKey: '1234',
+        zulipVersion: '6.0',
+        zulipMergeBase: const Value('6.0'),
+        zulipFeatureLevel: 42,
+      ));
+      final accountV1 = await before.select(before.accounts).watchSingle().first;
+      await before.close();
+
+      final db = AppDatabase(schema.newConnection());
+      await verifier.migrateAndValidate(db, 2);
+      await db.close();
+
+      final after = v2.DatabaseAtV2(schema.newConnection());
+      final account = await after.select(after.accounts).getSingle();
+      check(account.toJson()).deepEquals({
+        ...accountV1.toJson(),
+        'ackedPushToken': null,
+      });
     });
   });
 }

test/model/database_test.dart

@@ -0,0 +1 @@
+{"_meta":{"description":"This file contains a serialized version of schema entities for drift.","version":"1.0.0"},"options":{"store_date_time_values_as_text":false},"entities":[{"id":0,"references":[],"type":"table","data":{"name":"accounts","was_declared_in_moor":false,"columns":[{"name":"id","getter_name":"id","moor_type":"int","nullable":false,"customConstraints":null,"defaultConstraints":"PRIMARY KEY AUTOINCREMENT","default_dart":null,"default_client_dart":null,"dsl_features":["auto-increment"]},{"name":"realm_url","getter_name":"realmUrl","moor_type":"string","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"user_id","getter_name":"userId","moor_type":"int","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"email","getter_name":"email","moor_type":"string","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"api_key","getter_name":"apiKey","moor_type":"string","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"zulip_version","getter_name":"zulipVersion","moor_type":"string","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"zulip_merge_base","getter_name":"zulipMergeBase","moor_type":"string","nullable":true,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"zulip_feature_level","getter_name":"zulipFeatureLevel","moor_type":"int","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"acked_push_token","getter_name":"ackedPushToken","moor_type":"string","nullable":true,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]}],"is_virtual":false,"without_rowid":false,"constraints":[],"unique_keys":[["realm_url","user_id"],["realm_url","email"]]}}]}

test/model/schemas/drift_schema_v2.json

@@ -4,15 +4,18 @@
 import 'package:drift/drift.dart';
 import 'package:drift/internal/migrations.dart';
 import 'schema_v1.dart' as v1;
+import 'schema_v2.dart' as v2;
 
 class GeneratedHelper implements SchemaInstantiationHelper {
   @override
   GeneratedDatabase databaseForVersion(QueryExecutor db, int version) {
     switch (version) {
       case 1:
         return v1.DatabaseAtV1(db);
+      case 2:
+        return v2.DatabaseAtV2(db);
       default:
-        throw MissingSchemaException(version, const {1});
+        throw MissingSchemaException(version, const {1, 2});
     }
   }
 }