chore: Add benchmark for time and storage interference (#4)

benchmark/utils/benchmark.dart

@@ -0,0 +1,94 @@
+import 'dart:io';
+
+import 'package:benchmark_harness/benchmark_harness.dart';
+import 'package:drift_offline_sync/src/database/triggers.dart';
+import 'package:path/path.dart' as p;
+
+import 'database.dart';
+
+export 'package:drift_offline_sync/src/database/triggers.dart' show Operation;
+
+class CrdtBenchmark extends AsyncBenchmarkBase {
+  CrdtBenchmark(
+    super.name, {
+    required this.crdtEnabled,
+    required this.operation,
+    required this.rowCount,
+  });
+
+  final bool crdtEnabled;
+  final Operation operation;
+  final int rowCount;
+
+  late final CrdtBenchmarkDatabase _db;
+  late final File _dbFile;
+
+  int _lastDatabaseSize = 0;
+  int _lastRowsCount = 0;
+
+  @override
+  Future<void> setup() async {
+    final dbPath = p.join(Directory.systemTemp.path, 'benchmark_$name.db');
+    _dbFile = File(dbPath);
+    _db = CrdtBenchmarkDatabase.createDatabase(_dbFile, crdtEnabled: crdtEnabled);
+
+    // Force the migration to be applied during setup.
+    await _db.batchInsertTestRows(1);
+    await _db.deleteTestRows(1);
+    await _db.managers.tableWithEveryColumnType.delete();
+
+    if (operation != Operation.insert) {
+      await _db.batchInsertTestRows(rowCount);
+    }
+  }
+
+  /// The default warmup is to invoke the [run] method once, but this pollutes the
+  /// results by persisting data before the run.
+  @override
+  Future<void> warmup() async {}
+
+  @override
+  Future<void> run() async {
+    _lastDatabaseSize = 0;
+    _lastRowsCount = 0;
+    switch (operation) {
+      case Operation.insert:
+      case Operation.update:
+        await _db.upsertTestRows(rowCount);
+      case Operation.delete:
+        await _db.deleteTestRows(rowCount);
+    }
+  }
+
+  @override
+  Future<(double, int)> report() async {
+    final averageMicroseconds = await measure();
+    return (averageMicroseconds, measureStorage());
+  }
+
+  @override
+  Future<void> teardown() async {
+    _lastDatabaseSize = _dbFile.lengthSync();
+    _lastRowsCount = await _db.testRowsCount();
+    await _db.close();
+    if (_dbFile.existsSync()) {
+      _dbFile.deleteSync();
+    }
+  }
+
+  int measureStorage() {
+    if (operation == Operation.delete) {
+      return _lastDatabaseSize;
+    }
+
+    if (_lastDatabaseSize == 0) {
+      throw Exception('Last database size is not set.');
+    }
+    if (_lastRowsCount < rowCount) {
+      throw Exception('Rows count is $_lastRowsCount but expected at least $rowCount.');
+    }
+    // If the benchmark ran for more than one loop, it can contain a greater number
+    // of rows than the expected. We need to normalize it to the expected total.
+    return _lastDatabaseSize ~/ (_lastRowsCount / rowCount);
+  }
+}