diff --git a/packages/metrics_center/CHANGELOG.md b/packages/metrics_center/CHANGELOG.md
index 7fcef0fead..731d2ce8ea 100644
--- a/packages/metrics_center/CHANGELOG.md
+++ b/packages/metrics_center/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 1.0.0
+
+- Null safety support
+
 # 0.1.1
 
 - Update packages to null safe
diff --git a/packages/metrics_center/lib/src/common.dart b/packages/metrics_center/lib/src/common.dart
index fe98ff90e0..ca6cabddc7 100644
--- a/packages/metrics_center/lib/src/common.dart
+++ b/packages/metrics_center/lib/src/common.dart
@@ -16,11 +16,11 @@ class MetricPoint extends Equatable {
   /// Creates a new data point.
   MetricPoint(
     this.value,
-    Map<String, String> tags,
+    Map<String, String?> tags,
   ) : _tags = SplayTreeMap<String, String>.from(tags);
 
   /// Can store integer values.
-  final double value;
+  final double? value;
 
   /// Test name, unit, timestamp, configs, git revision, ..., in sorted order.
   UnmodifiableMapView<String, String> get tags =>
@@ -43,7 +43,7 @@ class MetricPoint extends Equatable {
   final SplayTreeMap<String, String> _tags;
 
   @override
-  List<Object> get props => <Object>[value, tags];
+  List<Object?> get props => <Object?>[value, tags];
 }
 
 /// Interface to write [MetricPoint].
diff --git a/packages/metrics_center/lib/src/gcs_lock.dart b/packages/metrics_center/lib/src/gcs_lock.dart
index c8ebe930f7..ca64f648c3 100644
--- a/packages/metrics_center/lib/src/gcs_lock.dart
+++ b/packages/metrics_center/lib/src/gcs_lock.dart
@@ -82,7 +82,7 @@ class GcsLock {
     await _api.objects.delete(_bucketName, lockFileName);
   }
 
-  StorageApi _api;
+  late StorageApi _api;
 
   final String _bucketName;
   final AuthClient _client;
diff --git a/packages/metrics_center/lib/src/google_benchmark.dart b/packages/metrics_center/lib/src/google_benchmark.dart
index 118167f628..bbb567dcf2 100644
--- a/packages/metrics_center/lib/src/google_benchmark.dart
+++ b/packages/metrics_center/lib/src/google_benchmark.dart
@@ -50,21 +50,21 @@ void _parseAnItem(
   };
   for (final String subResult in item.keys) {
     if (!_kNonNumericalValueSubResults.contains(subResult)) {
-      num rawValue;
+      num? rawValue;
       try {
-        rawValue = item[subResult] as num;
+        rawValue = item[subResult] as num?;
       } catch (e) {
         print(
             '$subResult: ${item[subResult]} (${item[subResult].runtimeType}) is not a number');
         rethrow;
       }
 
-      final double value =
-          rawValue is int ? rawValue.toDouble() : rawValue as double;
+      final double? value =
+          rawValue is int ? rawValue.toDouble() : rawValue as double?;
       points.add(
         MetricPoint(
           value,
-          <String, String>{kNameKey: name, kSubResultKey: subResult}
+          <String, String?>{kNameKey: name, kSubResultKey: subResult}
             ..addAll(context)
             ..addAll(
                 subResult.endsWith('time') ? timeUnitMap : <String, String>{}),
diff --git a/packages/metrics_center/lib/src/skiaperf.dart b/packages/metrics_center/lib/src/skiaperf.dart
index 063bad1d33..999b73481b 100644
--- a/packages/metrics_center/lib/src/skiaperf.dart
+++ b/packages/metrics_center/lib/src/skiaperf.dart
@@ -48,15 +48,15 @@ import 'gcs_lock.dart';
 /// ```
 class SkiaPerfPoint extends MetricPoint {
   SkiaPerfPoint._(this.githubRepo, this.gitHash, this.testName, this.subResult,
-      double value, this._options, this.jsonUrl)
+      double? value, this._options, this.jsonUrl)
       : assert(_options[kGithubRepoKey] == null),
         assert(_options[kGitRevisionKey] == null),
         assert(_options[kNameKey] == null),
         super(
           value,
-          <String, String>{}
+          <String, String?>{}
             ..addAll(_options)
-            ..addAll(<String, String>{
+            ..addAll(<String, String?>{
               kGithubRepoKey: githubRepo,
               kGitRevisionKey: gitHash,
               kNameKey: testName,
@@ -78,9 +78,9 @@ class SkiaPerfPoint extends MetricPoint {
   /// Skia perf will use the git revision's date instead of this date tag in
   /// the time axis.
   factory SkiaPerfPoint.fromPoint(MetricPoint p) {
-    final String githubRepo = p.tags[kGithubRepoKey];
-    final String gitHash = p.tags[kGitRevisionKey];
-    final String name = p.tags[kNameKey];
+    final String? githubRepo = p.tags[kGithubRepoKey];
+    final String? gitHash = p.tags[kGitRevisionKey];
+    final String? name = p.tags[kNameKey];
 
     if (githubRepo == null || gitHash == null || name == null) {
       throw '$kGithubRepoKey, $kGitRevisionKey, $kNameKey must be set in'
@@ -113,7 +113,7 @@ class SkiaPerfPoint extends MetricPoint {
   final String githubRepo;
 
   /// SHA such as 'ad20d368ffa09559754e4b2b5c12951341ca3b2d'
-  final String gitHash;
+  final String? gitHash;
 
   /// For Flutter devicelab, this is the task name (e.g.,
   /// 'flutter_gallery__transition_perf'); for Google benchmark, this is the
@@ -138,7 +138,7 @@ class SkiaPerfPoint extends MetricPoint {
   /// The url to the Skia perf json file in the Google Cloud Storage bucket.
   ///
   /// This can be null if the point has been stored in the bucket yet.
-  final String jsonUrl;
+  final String? jsonUrl;
 
   Map<String, dynamic> _toSubResultJson() {
     return <String, dynamic>{
@@ -260,7 +260,7 @@ class SkiaPerfGcsAdaptor {
   }
 
   Future<List<SkiaPerfPoint>> _readPointsWithoutRetry(String objectName) async {
-    ObjectInfo info;
+    ObjectInfo? info;
 
     try {
       info = await _gcsBucket.info(objectName);
@@ -282,10 +282,10 @@ class SkiaPerfGcsAdaptor {
 
     final String firstGcsNameComponent = objectName.split('/')[0];
     _populateGcsNameToGithubRepoMapIfNeeded();
-    final String githubRepo = _gcsNameToGithubRepo[firstGcsNameComponent];
+    final String githubRepo = _gcsNameToGithubRepo[firstGcsNameComponent]!;
     assert(githubRepo != null);
 
-    final String gitHash = decodedJson[kSkiaPerfGitHashKey] as String;
+    final String? gitHash = decodedJson[kSkiaPerfGitHashKey] as String?;
     final Map<String, dynamic> results =
         decodedJson[kSkiaPerfResultsKey] as Map<String, dynamic>;
     for (final String name in results.keys) {
@@ -298,7 +298,7 @@ class SkiaPerfGcsAdaptor {
           gitHash,
           name,
           subResult,
-          subResultMap[subResult] as double,
+          subResultMap[subResult] as double?,
           (subResultMap[kSkiaPerfOptionsKey] as Map<String, dynamic>)
               .cast<String, String>(),
           info.downloadLink.toString(),
@@ -317,9 +317,9 @@ class SkiaPerfGcsAdaptor {
   /// json files in the future to scale up the system if too many writes are
   /// competing for the same json file.
   static Future<String> computeObjectName(
-      String githubRepo, String revision, DateTime commitTime) async {
+      String githubRepo, String? revision, DateTime commitTime) async {
     assert(_githubRepoToGcsName[githubRepo] != null);
-    final String topComponent = _githubRepoToGcsName[githubRepo];
+    final String? topComponent = _githubRepoToGcsName[githubRepo];
     // [commitTime] is not guranteed to be UTC. Ensure it is so all results
     // pushed to GCS are the same timezone.
     final DateTime commitUtcTime = commitTime.toUtc();
@@ -334,12 +334,12 @@ class SkiaPerfGcsAdaptor {
     kFlutterFrameworkRepo: 'flutter-flutter',
     kFlutterEngineRepo: 'flutter-engine',
   };
-  static final Map<String, String> _gcsNameToGithubRepo = <String, String>{};
+  static final Map<String?, String> _gcsNameToGithubRepo = <String?, String>{};
 
   static void _populateGcsNameToGithubRepoMapIfNeeded() {
     if (_gcsNameToGithubRepo.isEmpty) {
       for (final String repo in _githubRepoToGcsName.keys) {
-        final String gcsName = _githubRepoToGcsName[repo];
+        final String? gcsName = _githubRepoToGcsName[repo];
         assert(_gcsNameToGithubRepo[gcsName] == null);
         _gcsNameToGithubRepo[gcsName] = repo;
       }
@@ -396,43 +396,43 @@ class SkiaPerfDestination extends MetricDestination {
     // 1st, create a map based on git repo, git revision, and point id. Git repo
     // and git revision are the top level components of the Skia perf GCS object
     // name.
-    final Map<String, Map<String, Map<String, SkiaPerfPoint>>> pointMap =
+    final Map<String, Map<String?, Map<String, SkiaPerfPoint>>> pointMap =
         <String, Map<String, Map<String, SkiaPerfPoint>>>{};
     for (final SkiaPerfPoint p
         in points.map((MetricPoint x) => SkiaPerfPoint.fromPoint(x))) {
       if (p != null) {
         pointMap[p.githubRepo] ??= <String, Map<String, SkiaPerfPoint>>{};
-        pointMap[p.githubRepo][p.gitHash] ??= <String, SkiaPerfPoint>{};
-        pointMap[p.githubRepo][p.gitHash][p.id] = p;
+        pointMap[p.githubRepo]![p.gitHash] ??= <String, SkiaPerfPoint>{};
+        pointMap[p.githubRepo]![p.gitHash]![p.id] = p;
       }
     }
 
     // 2nd, read existing points from the gcs object and update with new ones.
     for (final String repo in pointMap.keys) {
-      for (final String revision in pointMap[repo].keys) {
+      for (final String? revision in pointMap[repo]!.keys) {
         final String objectName = await SkiaPerfGcsAdaptor.computeObjectName(
             repo, revision, commitTime);
-        final Map<String, SkiaPerfPoint> newPoints = pointMap[repo][revision];
+        final Map<String, SkiaPerfPoint>? newPoints = pointMap[repo]![revision];
         // If too many bots are writing the metrics of a git revision into this
         // single json file (with name `objectName`), the contention on the lock
         // might be too high. In that case, break the json file into multiple
         // json files according to bot names or task names. Skia perf read all
         // json files in the directory so one can use arbitrary names for those
         // sharded json file names.
-        _lock.protectedRun('$objectName.lock', () async {
+        _lock!.protectedRun('$objectName.lock', () async {
           final List<SkiaPerfPoint> oldPoints =
               await _gcs.readPoints(objectName);
           for (final SkiaPerfPoint p in oldPoints) {
-            if (newPoints[p.id] == null) {
+            if (newPoints![p.id] == null) {
               newPoints[p.id] = p;
             }
           }
-          await _gcs.writePoints(objectName, newPoints.values.toList());
+          await _gcs.writePoints(objectName, newPoints!.values.toList());
         });
       }
     }
   }
 
   final SkiaPerfGcsAdaptor _gcs;
-  final GcsLock _lock;
+  late final GcsLock? _lock;
 }
diff --git a/packages/metrics_center/pubspec.yaml b/packages/metrics_center/pubspec.yaml
index 39218d3e45..3c7947c996 100644
--- a/packages/metrics_center/pubspec.yaml
+++ b/packages/metrics_center/pubspec.yaml
@@ -1,23 +1,24 @@
 name: metrics_center
-version: 0.1.1
+version: 1.0.0
 description:
   Support multiple performance metrics sources/formats and destinations.
 repository: https://github.com/flutter/packages/tree/master/packages/metrics_center
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+metrics_center%22
 
 environment:
-  sdk: '>=2.10.0 <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
-  crypto: ^3.0.0
-  equatable: ^1.2.5
-  gcloud: ^0.8.0
+  crypto: ^3.0.1
+  equatable: ^2.0.3
+  gcloud: ^0.8.2
   googleapis: ^3.0.0
-  googleapis_auth: ^1.0.0
+  googleapis_auth: ^1.1.0
   http: ^0.13.3
 
 dev_dependencies:
+  build_runner: ^2.1.1
   fake_async: ^1.2.0
-  mockito: ^5.0.0
-  pedantic: ^1.10.0
-  test: ^1.17.0
+  mockito: ^5.0.14
+  pedantic: ^1.11.1
+  test: ^1.17.11
diff --git a/packages/metrics_center/test/flutter_test.dart b/packages/metrics_center/test/flutter_test.dart
index 63b6e945a5..d50794d45b 100644
--- a/packages/metrics_center/test/flutter_test.dart
+++ b/packages/metrics_center/test/flutter_test.dart
@@ -38,11 +38,11 @@ void main() {
     expect(detailedPoint.tags[kUnitKey], equals('ns'));
   });
 
-  final Map<String, dynamic> credentialsJson = getTestGcpCredentialsJson();
+  final Map<String, dynamic>? credentialsJson = getTestGcpCredentialsJson();
 
   test('FlutterDestination integration test with update.', () async {
     final FlutterDestination dst =
-        await FlutterDestination.makeFromCredentialsJson(credentialsJson,
+        await FlutterDestination.makeFromCredentialsJson(credentialsJson!,
             isTesting: true);
     dst.update(<FlutterEngineMetricPoint>[simplePoint],
         DateTime.fromMillisecondsSinceEpoch(123));
diff --git a/packages/metrics_center/test/gcs_lock_test.dart b/packages/metrics_center/test/gcs_lock_test.dart
index 6e9c1e9a9c..b5228bf8f0 100644
--- a/packages/metrics_center/test/gcs_lock_test.dart
+++ b/packages/metrics_center/test/gcs_lock_test.dart
@@ -10,9 +10,11 @@ import 'package:googleapis/storage/v1.dart';
 import 'package:googleapis_auth/auth_io.dart';
 import 'package:metrics_center/src/constants.dart';
 import 'package:metrics_center/src/gcs_lock.dart';
+import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
 
 import 'common.dart';
+import 'gcs_lock_test.mocks.dart';
 import 'utility.dart';
 
 enum TestPhase {
@@ -20,11 +22,10 @@ enum TestPhase {
   run2,
 }
 
-class MockClient extends Mock implements AuthClient {}
-
+@GenerateMocks(<Type>[AuthClient])
 void main() {
   const Duration kDelayStep = Duration(milliseconds: 10);
-  final Map<String, dynamic> credentialsJson = getTestGcpCredentialsJson();
+  final Map<String, dynamic>? credentialsJson = getTestGcpCredentialsJson();
 
   test('GcsLock prints warnings for long waits', () {
     // Capture print to verify error messages.
@@ -34,7 +35,7 @@ void main() {
 
     Zone.current.fork(specification: spec).run<void>(() {
       fakeAsync((FakeAsync fakeAsync) {
-        final MockClient mockClient = MockClient();
+        final MockAuthClient mockClient = MockAuthClient();
         final GcsLock lock = GcsLock(mockClient, 'mockBucket');
         when(mockClient.send(any)).thenThrow(DetailedApiRequestError(412, ''));
         final Future<void> runFinished =
diff --git a/packages/metrics_center/test/gcs_lock_test.mocks.dart b/packages/metrics_center/test/gcs_lock_test.mocks.dart
new file mode 100644
index 0000000000..58b95a791e
--- /dev/null
+++ b/packages/metrics_center/test/gcs_lock_test.mocks.dart
@@ -0,0 +1,117 @@
+// Mocks generated by Mockito 5.0.14 from annotations
+// in metrics_center/test/gcs_lock_test.dart.
+// Do not manually edit this file.
+
+import 'dart:async' as _i5;
+import 'dart:convert' as _i6;
+import 'dart:typed_data' as _i7;
+
+import 'package:googleapis_auth/src/access_credentials.dart' as _i2;
+import 'package:googleapis_auth/src/auth_client.dart' as _i4;
+import 'package:http/http.dart' as _i3;
+import 'package:mockito/mockito.dart' as _i1;
+
+// ignore_for_file: always_specify_types
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: camel_case_types
+// ignore_for_file: comment_references
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_overrides
+// ignore_for_file: unnecessary_parenthesis
+
+class _FakeAccessCredentials_0 extends _i1.Fake
+    implements _i2.AccessCredentials {}
+
+class _FakeResponse_1 extends _i1.Fake implements _i3.Response {}
+
+class _FakeStreamedResponse_2 extends _i1.Fake implements _i3.StreamedResponse {
+}
+
+/// A class which mocks [AuthClient].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockAuthClient extends _i1.Mock implements _i4.AuthClient {
+  MockAuthClient() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i2.AccessCredentials get credentials =>
+      (super.noSuchMethod(Invocation.getter(#credentials),
+          returnValue: _FakeAccessCredentials_0()) as _i2.AccessCredentials);
+  @override
+  String toString() => super.toString();
+  @override
+  _i5.Future<_i3.Response> head(Uri? url, {Map<String, String>? headers}) =>
+      (super.noSuchMethod(Invocation.method(#head, [url], {#headers: headers}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<_i3.Response> get(Uri? url, {Map<String, String>? headers}) =>
+      (super.noSuchMethod(Invocation.method(#get, [url], {#headers: headers}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<_i3.Response> post(Uri? url,
+          {Map<String, String>? headers,
+          Object? body,
+          _i6.Encoding? encoding}) =>
+      (super.noSuchMethod(
+              Invocation.method(#post, [url],
+                  {#headers: headers, #body: body, #encoding: encoding}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<_i3.Response> put(Uri? url,
+          {Map<String, String>? headers,
+          Object? body,
+          _i6.Encoding? encoding}) =>
+      (super.noSuchMethod(
+              Invocation.method(#put, [url],
+                  {#headers: headers, #body: body, #encoding: encoding}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<_i3.Response> patch(Uri? url,
+          {Map<String, String>? headers,
+          Object? body,
+          _i6.Encoding? encoding}) =>
+      (super.noSuchMethod(
+              Invocation.method(#patch, [url],
+                  {#headers: headers, #body: body, #encoding: encoding}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<_i3.Response> delete(Uri? url,
+          {Map<String, String>? headers,
+          Object? body,
+          _i6.Encoding? encoding}) =>
+      (super.noSuchMethod(
+              Invocation.method(#delete, [url],
+                  {#headers: headers, #body: body, #encoding: encoding}),
+              returnValue: Future<_i3.Response>.value(_FakeResponse_1()))
+          as _i5.Future<_i3.Response>);
+  @override
+  _i5.Future<String> read(Uri? url, {Map<String, String>? headers}) =>
+      (super.noSuchMethod(Invocation.method(#read, [url], {#headers: headers}),
+          returnValue: Future<String>.value('')) as _i5.Future<String>);
+  @override
+  _i5.Future<_i7.Uint8List> readBytes(Uri? url,
+          {Map<String, String>? headers}) =>
+      (super.noSuchMethod(
+              Invocation.method(#readBytes, [url], {#headers: headers}),
+              returnValue: Future<_i7.Uint8List>.value(_i7.Uint8List(0)))
+          as _i5.Future<_i7.Uint8List>);
+  @override
+  _i5.Future<_i3.StreamedResponse> send(_i3.BaseRequest? request) =>
+      (super.noSuchMethod(Invocation.method(#send, [request]),
+              returnValue:
+                  Future<_i3.StreamedResponse>.value(_FakeStreamedResponse_2()))
+          as _i5.Future<_i3.StreamedResponse>);
+  @override
+  void close() => super.noSuchMethod(Invocation.method(#close, []),
+      returnValueForMissingStub: null);
+}
diff --git a/packages/metrics_center/test/skiaperf_test.dart b/packages/metrics_center/test/skiaperf_test.dart
index dcfedf068a..09eeed91eb 100644
--- a/packages/metrics_center/test/skiaperf_test.dart
+++ b/packages/metrics_center/test/skiaperf_test.dart
@@ -12,15 +12,13 @@ import 'package:googleapis_auth/auth_io.dart';
 import 'package:metrics_center/metrics_center.dart';
 import 'package:metrics_center/src/constants.dart';
 import 'package:metrics_center/src/gcs_lock.dart';
+import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';
 
 import 'common.dart';
+import 'skiaperf_test.mocks.dart';
 import 'utility.dart';
 
-class MockBucket extends Mock implements Bucket {}
-
-class MockObjectInfo extends Mock implements ObjectInfo {}
-
 class MockGcsLock implements GcsLock {
   @override
   Future<void> protectedRun(
@@ -46,6 +44,7 @@ class MockSkiaPerfGcsAdaptor implements SkiaPerfGcsAdaptor {
       <String, List<SkiaPerfPoint>>{};
 }
 
+@GenerateMocks(<Type>[Bucket, ObjectInfo])
 Future<void> main() async {
   const double kValue1 = 1.0;
   const double kValue2 = 2.0;
@@ -353,6 +352,8 @@ Future<void> main() async {
     ];
     final String skiaPerfJson =
         jsonEncode(SkiaPerfPoint.toSkiaPerfJson(writePoints));
+    when(testBucket.writeBytes(testObjectName, utf8.encode(skiaPerfJson)))
+        .thenAnswer((_) async => FakeObjectInfo());
     await skiaPerfGcs.writePoints(testObjectName, writePoints);
     verify(testBucket.writeBytes(testObjectName, utf8.encode(skiaPerfJson)));
 
@@ -392,9 +393,9 @@ Future<void> main() async {
   });
 
   // The following is for integration tests.
-  Bucket testBucket;
-  GcsLock testLock;
-  final Map<String, dynamic> credentialsJson = getTestGcpCredentialsJson();
+  Bucket? testBucket;
+  GcsLock? testLock;
+  final Map<String, dynamic>? credentialsJson = getTestGcpCredentialsJson();
   if (credentialsJson != null) {
     final ServiceAccountCredentials credentials =
         ServiceAccountCredentials.fromJson(credentialsJson);
@@ -412,7 +413,7 @@ Future<void> main() async {
   }
 
   Future<void> skiaPerfGcsAdapterIntegrationTest() async {
-    final SkiaPerfGcsAdaptor skiaPerfGcs = SkiaPerfGcsAdaptor(testBucket);
+    final SkiaPerfGcsAdaptor skiaPerfGcs = SkiaPerfGcsAdaptor(testBucket!);
 
     final String testObjectName = await SkiaPerfGcsAdaptor.computeObjectName(
         kFlutterFrameworkRepo,
@@ -443,7 +444,7 @@ Future<void> main() async {
   }
 
   Future<void> skiaPerfGcsIntegrationTestWithEnginePoints() async {
-    final SkiaPerfGcsAdaptor skiaPerfGcs = SkiaPerfGcsAdaptor(testBucket);
+    final SkiaPerfGcsAdaptor skiaPerfGcs = SkiaPerfGcsAdaptor(testBucket!);
 
     final String testObjectName = await SkiaPerfGcsAdaptor.computeObjectName(
         kFlutterEngineRepo,
@@ -569,7 +570,7 @@ Future<void> main() async {
 
   Future<void> skiaPerfDestinationIntegrationTest() async {
     final SkiaPerfDestination destination =
-        SkiaPerfDestination(SkiaPerfGcsAdaptor(testBucket), testLock);
+        SkiaPerfDestination(SkiaPerfGcsAdaptor(testBucket!), testLock);
     await destination.update(<MetricPoint>[cocoonPointRev1Metric1],
         DateTime.fromMillisecondsSinceEpoch(123));
   }
@@ -580,3 +581,32 @@ Future<void> main() async {
     skip: testBucket == null,
   );
 }
+
+class FakeObjectInfo extends ObjectInfo {
+  @override
+  int get crc32CChecksum => throw UnimplementedError();
+
+  @override
+  Uri get downloadLink => throw UnimplementedError();
+
+  @override
+  String get etag => throw UnimplementedError();
+
+  @override
+  ObjectGeneration get generation => throw UnimplementedError();
+
+  @override
+  int get length => throw UnimplementedError();
+
+  @override
+  List<int> get md5Hash => throw UnimplementedError();
+
+  @override
+  ObjectMetadata get metadata => throw UnimplementedError();
+
+  @override
+  String get name => throw UnimplementedError();
+
+  @override
+  DateTime get updated => throw UnimplementedError();
+}
diff --git a/packages/metrics_center/test/skiaperf_test.mocks.dart b/packages/metrics_center/test/skiaperf_test.mocks.dart
new file mode 100644
index 0000000000..515f8833fd
--- /dev/null
+++ b/packages/metrics_center/test/skiaperf_test.mocks.dart
@@ -0,0 +1,175 @@
+// Mocks generated by Mockito 5.0.14 from annotations
+// in metrics_center/test/skiaperf_test.dart.
+// Do not manually edit this file.
+
+import 'dart:async' as _i2;
+
+import 'package:gcloud/common.dart' as _i4;
+import 'package:gcloud/storage.dart' as _i3;
+import 'package:mockito/mockito.dart' as _i1;
+
+// ignore_for_file: always_specify_types
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: camel_case_types
+// ignore_for_file: comment_references
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_overrides
+// ignore_for_file: unnecessary_parenthesis
+
+class _FakeStreamSink_0<S> extends _i1.Fake implements _i2.StreamSink<S> {}
+
+class _FakeObjectInfo_1 extends _i1.Fake implements _i3.ObjectInfo {}
+
+class _FakePage_2<T> extends _i1.Fake implements _i4.Page<T> {}
+
+class _FakeDateTime_3 extends _i1.Fake implements DateTime {}
+
+class _FakeUri_4 extends _i1.Fake implements Uri {}
+
+class _FakeObjectGeneration_5 extends _i1.Fake implements _i3.ObjectGeneration {
+}
+
+class _FakeObjectMetadata_6 extends _i1.Fake implements _i3.ObjectMetadata {}
+
+/// A class which mocks [Bucket].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockBucket extends _i1.Mock implements _i3.Bucket {
+  MockBucket() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  String get bucketName =>
+      (super.noSuchMethod(Invocation.getter(#bucketName), returnValue: '')
+          as String);
+  @override
+  String absoluteObjectName(String? objectName) =>
+      (super.noSuchMethod(Invocation.method(#absoluteObjectName, [objectName]),
+          returnValue: '') as String);
+  @override
+  _i2.StreamSink<List<int>> write(String? objectName,
+          {int? length,
+          _i3.ObjectMetadata? metadata,
+          _i3.Acl? acl,
+          _i3.PredefinedAcl? predefinedAcl,
+          String? contentType}) =>
+      (super.noSuchMethod(
+              Invocation.method(#write, [
+                objectName
+              ], {
+                #length: length,
+                #metadata: metadata,
+                #acl: acl,
+                #predefinedAcl: predefinedAcl,
+                #contentType: contentType
+              }),
+              returnValue: _FakeStreamSink_0<List<int>>())
+          as _i2.StreamSink<List<int>>);
+  @override
+  _i2.Future<_i3.ObjectInfo> writeBytes(String? name, List<int>? bytes,
+          {_i3.ObjectMetadata? metadata,
+          _i3.Acl? acl,
+          _i3.PredefinedAcl? predefinedAcl,
+          String? contentType}) =>
+      (super.noSuchMethod(
+              Invocation.method(#writeBytes, [
+                name,
+                bytes
+              ], {
+                #metadata: metadata,
+                #acl: acl,
+                #predefinedAcl: predefinedAcl,
+                #contentType: contentType
+              }),
+              returnValue: Future<_i3.ObjectInfo>.value(_FakeObjectInfo_1()))
+          as _i2.Future<_i3.ObjectInfo>);
+  @override
+  _i2.Stream<List<int>> read(String? objectName, {int? offset, int? length}) =>
+      (super.noSuchMethod(
+          Invocation.method(
+              #read, [objectName], {#offset: offset, #length: length}),
+          returnValue: Stream<List<int>>.empty()) as _i2.Stream<List<int>>);
+  @override
+  _i2.Future<_i3.ObjectInfo> info(String? name) =>
+      (super.noSuchMethod(Invocation.method(#info, [name]),
+              returnValue: Future<_i3.ObjectInfo>.value(_FakeObjectInfo_1()))
+          as _i2.Future<_i3.ObjectInfo>);
+  @override
+  _i2.Future<dynamic> delete(String? name) =>
+      (super.noSuchMethod(Invocation.method(#delete, [name]),
+          returnValue: Future<dynamic>.value()) as _i2.Future<dynamic>);
+  @override
+  _i2.Future<dynamic> updateMetadata(
+          String? objectName, _i3.ObjectMetadata? metadata) =>
+      (super.noSuchMethod(
+          Invocation.method(#updateMetadata, [objectName, metadata]),
+          returnValue: Future<dynamic>.value()) as _i2.Future<dynamic>);
+  @override
+  _i2.Stream<_i3.BucketEntry> list({String? prefix, String? delimiter}) =>
+      (super.noSuchMethod(
+              Invocation.method(
+                  #list, [], {#prefix: prefix, #delimiter: delimiter}),
+              returnValue: Stream<_i3.BucketEntry>.empty())
+          as _i2.Stream<_i3.BucketEntry>);
+  @override
+  _i2.Future<_i4.Page<_i3.BucketEntry>> page(
+          {String? prefix, String? delimiter, int? pageSize = 50}) =>
+      (super.noSuchMethod(
+              Invocation.method(#page, [], {
+                #prefix: prefix,
+                #delimiter: delimiter,
+                #pageSize: pageSize
+              }),
+              returnValue: Future<_i4.Page<_i3.BucketEntry>>.value(
+                  _FakePage_2<_i3.BucketEntry>()))
+          as _i2.Future<_i4.Page<_i3.BucketEntry>>);
+  @override
+  String toString() => super.toString();
+}
+
+/// A class which mocks [ObjectInfo].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockObjectInfo extends _i1.Mock implements _i3.ObjectInfo {
+  MockObjectInfo() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  String get name =>
+      (super.noSuchMethod(Invocation.getter(#name), returnValue: '') as String);
+  @override
+  int get length =>
+      (super.noSuchMethod(Invocation.getter(#length), returnValue: 0) as int);
+  @override
+  DateTime get updated => (super.noSuchMethod(Invocation.getter(#updated),
+      returnValue: _FakeDateTime_3()) as DateTime);
+  @override
+  String get etag =>
+      (super.noSuchMethod(Invocation.getter(#etag), returnValue: '') as String);
+  @override
+  List<int> get md5Hash =>
+      (super.noSuchMethod(Invocation.getter(#md5Hash), returnValue: <int>[])
+          as List<int>);
+  @override
+  int get crc32CChecksum =>
+      (super.noSuchMethod(Invocation.getter(#crc32CChecksum), returnValue: 0)
+          as int);
+  @override
+  Uri get downloadLink => (super.noSuchMethod(Invocation.getter(#downloadLink),
+      returnValue: _FakeUri_4()) as Uri);
+  @override
+  _i3.ObjectGeneration get generation =>
+      (super.noSuchMethod(Invocation.getter(#generation),
+          returnValue: _FakeObjectGeneration_5()) as _i3.ObjectGeneration);
+  @override
+  _i3.ObjectMetadata get metadata =>
+      (super.noSuchMethod(Invocation.getter(#metadata),
+          returnValue: _FakeObjectMetadata_6()) as _i3.ObjectMetadata);
+  @override
+  String toString() => super.toString();
+}
diff --git a/packages/metrics_center/test/utility.dart b/packages/metrics_center/test/utility.dart
index 31808a5730..f0c8e07894 100644
--- a/packages/metrics_center/test/utility.dart
+++ b/packages/metrics_center/test/utility.dart
@@ -13,11 +13,11 @@ void expectSetMatch<T>(Iterable<T> actual, Iterable<T> expected) {
 }
 
 // May return null if the credentials file doesn't exist.
-Map<String, dynamic> getTestGcpCredentialsJson() {
+Map<String, dynamic>? getTestGcpCredentialsJson() {
   final File f = File('secret/test_gcp_credentials.json');
   if (!f.existsSync()) {
     return null;
   }
   return jsonDecode(File('secret/test_gcp_credentials.json').readAsStringSync())
-      as Map<String, dynamic>;
+      as Map<String, dynamic>?;
 }