feat: Basic implementation of the OfflineSyncCrdt methods on SQLite3

test/crdt/crdt_save_changeset_test.dart

@@ -0,0 +1,164 @@
+import 'package:drift/drift.dart' hide isNotNull, isNull;
+import 'package:drift_offline_first/drift_offline_first.dart';
+import 'package:test/test.dart';
+import 'package:uuid/uuid.dart';
+
+import '../utils/crdt_context.dart';
+import '../utils/database.dart';
+import '../utils/tables.dart';
+
+void main() {
+  late OfflineSyncCrdt crdt;
+  late CrdtDatabase crdtDb;
+  late String otherNodeId;
+
+  group('Given CRDT for an empty database and a pending changeset', () {
+    late Iterable<CrdtDataEntry> changeset;
+    late Hlc lastHlc;
+
+    setUp(() async {
+      (crdt, crdtDb, _) = database.crdtContext;
+      otherNodeId = const Uuid().v4();
+
+      final todo = TodoEntry(
+        id: const RowId(1),
+        content: 'test',
+        targetDate: DateTime.now(),
+      );
+
+      changeset = todo.toCrdtDataEntry(otherNodeId);
+      lastHlc = Hlc.now(otherNodeId);
+    });
+
+    group('when saving a changeset', () {
+      setUp(() async {
+        await crdt.saveChangeset(changeset, [lastHlc]);
+      });
+
+      test('then the changeset is saved to the database.', () async {
+        final savedChangeset = await crdtDb.managers.crdtDataTable.get();
+        expect(savedChangeset, changeset);
+      });
+
+      test('then the merged HLCs are saved to the database.', () async {
+        final savedMergedHlcs = await crdtDb.managers.crdtMergeHlcTable.get();
+        expect(savedMergedHlcs.map((e) => e.lastReceivedHlc).single, lastHlc);
+      });
+    });
+  });
+
+  group(
+      'Given CRDT for a database with data and a pending changeset with conflicting data and older HLC',
+      () {
+    late Iterable<CrdtDataEntry> firstChangeset;
+    late Iterable<CrdtDataEntry> lateOldChangeset;
+    late Hlc lastHlc;
+    late Hlc lateOldHlc;
+
+    setUp(() async {
+      (crdt, crdtDb, _) = database.crdtContext;
+      otherNodeId = const Uuid().v4();
+
+      final todo = TodoEntry(
+        id: const RowId(1),
+        content: 'test',
+        targetDate: DateTime.now(),
+      );
+
+      lastHlc = Hlc.now(otherNodeId);
+      firstChangeset = todo.toCrdtDataEntry(otherNodeId, lastHlc);
+      await crdt.saveChangeset(firstChangeset, [lastHlc]);
+
+      lateOldHlc = Hlc.zero(otherNodeId);
+      lateOldChangeset = todo.toCrdtDataEntry(otherNodeId, lateOldHlc);
+    });
+
+    group('when saving a changeset with older HLC', () {
+      setUp(() async {
+        await crdt.saveChangeset(lateOldChangeset, [lateOldHlc]);
+      });
+
+      test('then no changes are saved to the database.', () async {
+        final savedChangeset = await crdtDb.managers.crdtDataTable.get();
+        expect(savedChangeset, firstChangeset);
+      });
+
+      test('then the last received HLC is not updated in the database.', () async {
+        final savedMergedHlcs = await crdtDb.managers.crdtMergeHlcTable.get();
+        expect(savedMergedHlcs.map((e) => e.lastReceivedHlc).single, lastHlc);
+      });
+    });
+  });
+
+  group(
+      'Given CRDT for a database with data and a pending changeset with conflicting data and some entries with newer HLC',
+      () {
+    late Iterable<CrdtDataEntry> firstChangeset;
+    late Iterable<CrdtDataEntry> newerChangeset;
+    late Hlc lastHlc;
+    late Hlc newerHlc;
+
+    setUp(() async {
+      (crdt, crdtDb, _) = database.crdtContext;
+      otherNodeId = const Uuid().v4();
+
+      final todo = TodoEntry(
+        id: const RowId(1),
+        content: 'test',
+        targetDate: DateTime.now(),
+      );
+
+      lastHlc = Hlc.now(otherNodeId);
+      firstChangeset = todo.toCrdtDataEntry(otherNodeId);
+      await crdt.saveChangeset(firstChangeset, [lastHlc]);
+
+      newerHlc = Hlc.now(otherNodeId);
+      newerChangeset = todo
+          .toCrdtDataEntry(otherNodeId, newerHlc)
+          .where((e) => e.columnName == 'content');
+    });
+
+    group('when saving a changeset with some entries with newer HLC', () {
+      setUp(() async {
+        await crdt.saveChangeset(newerChangeset, [newerHlc]);
+      });
+
+      test('then the entries with newer HLC are saved to the database.', () async {
+        final expectedResultingChangeset = [
+          for (final e in firstChangeset)
+            if (e.columnName == 'content') newerChangeset.first else e,
+        ];
+
+        expect(await crdtDb.managers.crdtDataTable.get(), expectedResultingChangeset);
+      });
+
+      test('then the last received HLC is updated in the database.', () async {
+        final savedMergedHlcs = await crdtDb.managers.crdtMergeHlcTable.get();
+        expect(savedMergedHlcs.map((e) => e.lastReceivedHlc).single, newerHlc);
+      });
+    });
+  });
+}
+
+extension on TodoEntry {
+  Iterable<CrdtDataEntry> toCrdtDataEntry(String nodeId, [Hlc? hlc]) {
+    final hlcTimestamp = hlc ?? Hlc.now(nodeId);
+
+    return database.todosTable.$columns.map(
+      (c) => CrdtDataEntry(
+        userId: 'test',
+        tblName: 'todos',
+        columnName: c.$name,
+        rowId: id.toString(),
+        rawValue: (toJson()[c.$name] as Object?)?.toDriftAny(),
+        hlcTimestamp: hlcTimestamp,
+      ),
+    );
+  }
+}
+
+extension on Object {
+  DriftAny? toDriftAny() {
+    return DriftAny(this);
+  }
+}