wip db: Add a migration, and a migration test

TODO change that generated_migrations pathname

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

.gitattributes

@@ -3,6 +3,10 @@
 # Dart files generated from the files next to them:
 *.g.dart -diff
 
+# Generated files for testing migrations:
+test/model/generated_migrations/*.dart -diff
+test/model/schemas/*.json -diff
+
 # On the other hand, keep diffs for pubspec.lock.  It contains
 # information independent of any non-generated file in the tree.
 # And thankfully it's much less verbose than, say, a yarn.lock.

analysis_options.yaml

@@ -26,5 +26,10 @@ linter:
     # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
     prefer_relative_imports: true
 
+analyzer:
+  exclude:
+    # https://github.com/simolus3/drift/issues/2337
+    - test/**/schema_v*.dart
+
 # Additional information about this file can be found at
 # https://dart.dev/guides/language/analysis-options

lib/model/database.dart

@@ -19,6 +19,8 @@ class Accounts extends Table {
   Column<String> get zulipVersion => text()();
   Column<int>    get zulipFeatureLevel => integer()();
 
+  Column<String> get ackedPushToken => text().nullable()();
+
   @override
   List<Set<Column<Object>>> get uniqueKeys => [
     {realmUrl, userId},
@@ -41,8 +43,30 @@ class AppDatabase extends _$AppDatabase {
 
   AppDatabase.live() : this(_openConnection());
 
+  // When updating the schema:
+  //  * Make the change in the table classes, and bump schemaVersion.
+  //  * Export the new schema:
+  //    $ dart run drift_dev schema dump lib/model/database.dart test/model/schemas/
+  //  * Generate test migrations from the schemas:
+  //    $ dart run drift_dev schema generate --data-classes --companions test/model/schemas/ test/model/generated_migrations/
+  //  * Write a migration in `onUpgrade` below.
+  //  * Write tests.
+  @override
+  int get schemaVersion => 2; // See note.
+
   @override
-  int get schemaVersion => 1; // TODO migrations
+  MigrationStrategy get migration {
+    return MigrationStrategy(
+      onCreate: (Migrator m) async {
+        await m.createAll();
+      },
+      onUpgrade: (Migrator m, int from, int to) async {
+        if (from < 2 && 2 <= to) {
+          await m.addColumn(accounts, accounts.ackedPushToken);
+        }
+      }
+    );
+  }
 
   Future<int> createAccount(AccountsCompanion values) {
     return into(accounts).insert(values);

lib/model/database.g.dart

@@ -1,36 +1,85 @@
 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 'generated_migrations/schema.dart';
+import 'generated_migrations/schema_v1.dart' as v1;
+import 'generated_migrations/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: 'https://chat.example/',
+        userId: 1,
+        email: '[email protected]',
+        apiKey: '1234',
+        zulipVersion: '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 {
-    final accountData = AccountsCompanion.insert(
-      realmUrl: 'https://chat.example/',
-      userId: 1,
-      email: '[email protected]',
-      apiKey: '1234',
-      zulipVersion: '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',
+        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,
+      });
     });
   });
 }