Add API to integrate with testWidgets.

pkgs/leak_tracker_flutter_testing/lib/leak_tracker_flutter_testing.dart

@@ -5,3 +5,7 @@
 export 'src/matchers.dart';
 export 'src/model.dart';
 export 'src/test_widgets.dart';
+export 'src/testing.dart';
+export 'package:leak_tracker/leak_tracker.dart'
+    show LeakTesting, Leaks, LeakTracking, IgnoredLeaks, LeakType, LeakReport;
+export 'package:leak_tracker_testing/leak_tracker_testing.dart' show isLeakFree;

pkgs/leak_tracker_flutter_testing/lib/src/testing.dart

@@ -0,0 +1,99 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:flutter/foundation.dart';
+import 'package:leak_tracker/leak_tracker.dart';
+import 'package:leak_tracker_testing/leak_tracker_testing.dart';
+import 'package:matcher/expect.dart';
+
+void mayBeSetupLeakTrackingForTest(
+  LeakTesting settings,
+  String testDescription,
+) {
+  if (settings.ignore) return;
+
+  if (!_checkPlatformAndMayBePrintWarning(
+      platformName: defaultTargetPlatform.name, isBrowser: kIsWeb)) {
+    return;
+  }
+
+  _maybeStartLeakTracking();
+
+  final PhaseSettings phase = PhaseSettings(
+    name: testDescription,
+    leakDiagnosticConfig: settings.leakDiagnosticConfig,
+    ignoredLeaks: settings.ignoredLeaks,
+    baselining: settings.baselining,
+    ignoreLeaks: settings.ignore,
+  );
+
+  LeakTracking.phase = phase;
+}
+
+void ignoreAllLeaks() {
+  LeakTracking.phase = const PhaseSettings.ignored();
+}
+
+/// Should be invoked after execution of all tests to report found leaks.
+Future<void> maybeTearDownLeakTracking() async {
+  if (!LeakTracking.isStarted) {
+    return;
+  }
+
+  MemoryAllocations.instance.removeListener(_dispatchFlutterEventToLeakTracker);
+  LeakTracking.declareNotDisposedObjectsAsLeaks();
+  await forceGC(fullGcCycles: defaultNumberOfGcCycles);
+  final Leaks leaks = await LeakTracking.collectLeaks();
+  LeakTracking.stop();
+
+  collectedLeaksReporter(leaks);
+}
+
+/// Handler for memory leaks found in tests.
+///
+/// Set it to analyse the leaks programmatically.
+/// The handler is invoked on tear down of the test run.
+/// The default reporter fails in case of found leaks.
+///
+/// Used to test leak tracking functionality.
+LeaksCallback collectedLeaksReporter =
+    (Leaks leaks) => expect(leaks, isLeakFree);
+
+void _dispatchFlutterEventToLeakTracker(ObjectEvent event) {
+  return LeakTracking.dispatchObjectEvent(event.toMap());
+}
+
+bool _notSupportedWarningPrinted = false;
+
+/// Checks if platform supported and, if no, prints warning if the warning is needed.
+///
+/// Warning is printed one time if `LeakTracking.warnForNotSupportedPlatforms` is true.
+bool _checkPlatformAndMayBePrintWarning(
+    {required String platformName, required bool isBrowser}) {
+  final isSupported = !isBrowser;
+
+  if (isSupported) return true;
+
+  final shouldPrintWarning =
+      LeakTracking.warnForUnsupportedPlatforms && !_notSupportedWarningPrinted;
+
+  if (!shouldPrintWarning) return false;
+
+  _notSupportedWarningPrinted = true;
+  debugPrint(
+    "Leak tracking is not supported on the platform '$platformName'.\n"
+    'To turn off this message, set `LeakTracking.warnForNotSupportedPlatforms` to false.',
+  );
+
+  return false;
+}
+
+/// Starts leak tracking with all leaks ignored.
+void _maybeStartLeakTracking() {
+  if (LeakTracking.isStarted) return;
+
+  LeakTracking.phase = const PhaseSettings.ignored();
+  LeakTracking.start(config: LeakTrackingConfig.passive());
+  MemoryAllocations.instance.addListener(_dispatchFlutterEventToLeakTracker);
+}

pkgs/leak_tracker_flutter_testing/pubspec.yaml

@@ -13,6 +13,7 @@ dependencies:
     sdk: flutter
   leak_tracker: ^9.0.10
   leak_tracker_testing: ^1.0.5
+  matcher: ^0.12.16
   meta: ^1.8.0
 
 dev_dependencies: