From 89f5f94c1b9e83ff200f764befd34d155544f36d Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Tue, 1 Oct 2019 16:34:12 -0700
Subject: [PATCH 01/17] CocoonResponse

---
 app_flutter/lib/state/flutter_build.dart | 29 +++++++++++++++++-------
 app_flutter/lib/status_grid.dart         |  6 ++---
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index 8ad36c065d..86fc2ee257 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -30,11 +30,14 @@ class FlutterBuildState extends ChangeNotifier {
   Timer refreshTimer;
 
   /// The current status of the commits loaded.
-  List<CommitStatus> statuses = <CommitStatus>[];
+  final CocoonResponse<List<CommitStatus>> _statuses =
+      CocoonResponse<List<CommitStatus>>()..data = <CommitStatus>[];
+  CocoonResponse<List<CommitStatus>> get statuses => _statuses;
 
   /// Whether or not flutter/flutter currently passes tests.
-  bool get isTreeBuilding => _isTreeBuilding;
-  bool _isTreeBuilding = true;
+  final CocoonResponse<bool> _isTreeBuilding = CocoonResponse<bool>()
+    ..data = false;
+  CocoonResponse<bool> get isTreeBuilding => _isTreeBuilding;
 
   /// Start a fixed interval loop that fetches build state updates based on [refreshRate].
   Future<void> startFetchingBuildStateUpdates() async {
@@ -52,12 +55,17 @@ class FlutterBuildState extends ChangeNotifier {
 
   /// Request the latest [statuses] from [CocoonService].
   Future<void> _fetchBuildStatusUpdate() async {
-    await Future.wait<void>(<Future<void>>[
-      _cocoonService.fetchCommitStatuses().then<List<CommitStatus>>(
-          (List<CommitStatus> commitStatuses) => statuses = commitStatuses),
+    await Future.wait(<Future<void>>[
       _cocoonService
-          .fetchTreeBuildStatus()
-          .then<bool>((bool treeStatus) => _isTreeBuilding = treeStatus),
+          .fetchCommitStatuses()
+          .then((List<CommitStatus> commitStatuses) {
+        _statuses.data = commitStatuses;
+        _statuses.error = null;
+      }),
+      _cocoonService.fetchTreeBuildStatus().then((bool treeStatus) {
+        _isTreeBuilding.data = treeStatus;
+        _isTreeBuilding.error = null;
+      }),
     ]);
 
     notifyListeners();
@@ -69,3 +77,8 @@ class FlutterBuildState extends ChangeNotifier {
     super.dispose();
   }
 }
+
+class CocoonResponse<T> {
+  T data;
+  String error;
+}
diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index eefc7a2b55..993067f2c0 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -23,10 +23,10 @@ class StatusGridContainer extends StatelessWidget {
   Widget build(BuildContext context) {
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
-        final List<CommitStatus> statuses = buildState.statuses;
+        CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;
 
         // Assume if there is no data that it is loading.
-        if (statuses.isEmpty) {
+        if (statuses.data.isEmpty) {
           return const Expanded(
             child: Center(
               child: CircularProgressIndicator(),
@@ -35,7 +35,7 @@ class StatusGridContainer extends StatelessWidget {
         }
 
         return StatusGrid(
-          statuses: statuses,
+          statuses: statuses.data,
         );
       },
     );

From fd8712cb8aead7a1d84dbdc212bd6050c59ecd44 Mon Sep 17 00:00:00 2001
From: Casey Hillers <caseyhillers@gmail.com>
Date: Wed, 2 Oct 2019 09:44:36 -0700
Subject: [PATCH 02/17] show snackbar when there is an error

---
 app_flutter/lib/service/fake_cocoon.dart |  1 +
 app_flutter/lib/state/flutter_build.dart |  3 +++
 app_flutter/lib/status_grid.dart         | 13 ++++++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/app_flutter/lib/service/fake_cocoon.dart b/app_flutter/lib/service/fake_cocoon.dart
index 7f2e9d68cd..2e4275d6cb 100644
--- a/app_flutter/lib/service/fake_cocoon.dart
+++ b/app_flutter/lib/service/fake_cocoon.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:io';
 import 'dart:math';
 
 import 'package:fixnum/fixnum.dart';
diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index 86fc2ee257..ad2cfde0a1 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -61,6 +61,9 @@ class FlutterBuildState extends ChangeNotifier {
           .then((List<CommitStatus> commitStatuses) {
         _statuses.data = commitStatuses;
         _statuses.error = null;
+      }, onError: (Exception error) {
+        _statuses.error = error.toString();
+        print('error occurred');
       }),
       _cocoonService.fetchTreeBuildStatus().then((bool treeStatus) {
         _isTreeBuilding.data = treeStatus;
diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index 993067f2c0..ac034dcddf 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -21,9 +21,20 @@ class StatusGridContainer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final ThemeData theme = Theme.of(context);
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
-        CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;
+        final CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;
+        if (statuses.error != null) {
+          print('there was an error!');
+          final SnackBar snackbar = SnackBar(
+            content: const Text('Failed to get the latest commit statuses'),
+            backgroundColor: theme.errorColor,
+            duration: const Duration(seconds: 10),
+            behavior: SnackBarBehavior.floating,
+          );
+          Scaffold.of(context).showSnackBar(snackbar);
+        }
 
         // Assume if there is no data that it is loading.
         if (statuses.data.isEmpty) {

From efa41de6911fd2bf520e4dd5bbf6a9f87036c6b5 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 11:00:00 -0700
Subject: [PATCH 03/17] moved error handling to parent BuildDashboard

---
 app_flutter/lib/build_dashboard.dart     | 38 ++++++++++++++++--------
 app_flutter/lib/service/fake_cocoon.dart |  1 -
 app_flutter/lib/state/flutter_build.dart | 16 ++++++----
 app_flutter/lib/status_grid.dart         | 10 -------
 4 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/app_flutter/lib/build_dashboard.dart b/app_flutter/lib/build_dashboard.dart
index e5a46ae261..2778c47b30 100644
--- a/app_flutter/lib/build_dashboard.dart
+++ b/app_flutter/lib/build_dashboard.dart
@@ -44,20 +44,34 @@ class _BuildDashboardPageState extends State<BuildDashboardPage> {
 class BuildDashboard extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
+    final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
     final ThemeData theme = Theme.of(context);
     return Consumer<FlutterBuildState>(
-      builder: (_, FlutterBuildState buildState, Widget child) => Scaffold(
-        appBar: AppBar(
-          title: const Text('Flutter Build Dashboard v2'),
-          backgroundColor:
-              buildState.isTreeBuilding ? theme.primaryColor : theme.errorColor,
-        ),
-        body: Column(
-          children: const <Widget>[
-            StatusGridContainer(),
-          ],
-        ),
-      ),
+      builder: (_, FlutterBuildState buildState, Widget child) {
+        if (buildState.hasError) {
+          const SnackBar snackbar = SnackBar(
+            content: Text('Cocoon Backend is having issues'),
+            duration: Duration(seconds: 10),
+            behavior: SnackBarBehavior.floating,
+          );
+          _scaffoldKey.currentState.showSnackBar(snackbar);
+        }
+
+        return Scaffold(
+          key: _scaffoldKey,
+          appBar: AppBar(
+            title: const Text('Flutter Build Dashboard v2'),
+            backgroundColor: buildState.isTreeBuilding.data
+                ? theme.primaryColor
+                : theme.errorColor,
+          ),
+          body: Column(
+            children: const <Widget>[
+              StatusGridContainer(),
+            ],
+          ),
+        );
+      },
     );
   }
 }
diff --git a/app_flutter/lib/service/fake_cocoon.dart b/app_flutter/lib/service/fake_cocoon.dart
index 2e4275d6cb..7f2e9d68cd 100644
--- a/app_flutter/lib/service/fake_cocoon.dart
+++ b/app_flutter/lib/service/fake_cocoon.dart
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:io';
 import 'dart:math';
 
 import 'package:fixnum/fixnum.dart';
diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index ad2cfde0a1..13cb688d37 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -39,6 +39,9 @@ class FlutterBuildState extends ChangeNotifier {
     ..data = false;
   CocoonResponse<bool> get isTreeBuilding => _isTreeBuilding;
 
+  /// Whether an error occured getting the latest data for the fields of this state.
+  bool get hasError => _isTreeBuilding.error ?? _statuses.error ?? false;
+
   /// Start a fixed interval loop that fetches build state updates based on [refreshRate].
   Future<void> startFetchingBuildStateUpdates() async {
     if (refreshTimer != null) {
@@ -56,18 +59,18 @@ class FlutterBuildState extends ChangeNotifier {
   /// Request the latest [statuses] from [CocoonService].
   Future<void> _fetchBuildStatusUpdate() async {
     await Future.wait(<Future<void>>[
-      _cocoonService
-          .fetchCommitStatuses()
-          .then((List<CommitStatus> commitStatuses) {
+      _cocoonService.fetchCommitStatuses().then(
+          (List<CommitStatus> commitStatuses) {
         _statuses.data = commitStatuses;
         _statuses.error = null;
-      }, onError: (Exception error) {
+      }, onError: (dynamic error) {
         _statuses.error = error.toString();
-        print('error occurred');
       }),
       _cocoonService.fetchTreeBuildStatus().then((bool treeStatus) {
         _isTreeBuilding.data = treeStatus;
         _isTreeBuilding.error = null;
+      }, onError: (dynamic error) {
+        _isTreeBuilding.error = error.toString();
       }),
     ]);
 
@@ -81,6 +84,9 @@ class FlutterBuildState extends ChangeNotifier {
   }
 }
 
+/// Wrapper class for data in this state.
+///
+/// Holds [data] and information for errors.
 class CocoonResponse<T> {
   T data;
   String error;
diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index ac034dcddf..97c7658394 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -25,16 +25,6 @@ class StatusGridContainer extends StatelessWidget {
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
         final CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;
-        if (statuses.error != null) {
-          print('there was an error!');
-          final SnackBar snackbar = SnackBar(
-            content: const Text('Failed to get the latest commit statuses'),
-            backgroundColor: theme.errorColor,
-            duration: const Duration(seconds: 10),
-            behavior: SnackBarBehavior.floating,
-          );
-          Scaffold.of(context).showSnackBar(snackbar);
-        }
 
         // Assume if there is no data that it is loading.
         if (statuses.data.isEmpty) {

From 30796695349e2204b5d37e3fa0f8213758531e74 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 11:15:19 -0700
Subject: [PATCH 04/17] better documentation

---
 app_flutter/lib/build_dashboard.dart     | 5 +++++
 app_flutter/lib/state/flutter_build.dart | 9 ++++++---
 app_flutter/lib/status_grid.dart         | 1 -
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/app_flutter/lib/build_dashboard.dart b/app_flutter/lib/build_dashboard.dart
index 2778c47b30..e0c2a14bf0 100644
--- a/app_flutter/lib/build_dashboard.dart
+++ b/app_flutter/lib/build_dashboard.dart
@@ -49,6 +49,11 @@ class BuildDashboard extends StatelessWidget {
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
         if (buildState.hasError) {
+          print('FlutterBuildState has an error');
+          print('isTreeBuilding: ${buildState.isTreeBuilding.error}');
+          print('statuses: ${buildState.statuses.error}');
+
+          // TODO(chillers): Make this display better on the TV by using a bigger widget.
           const SnackBar snackbar = SnackBar(
             content: Text('Cocoon Backend is having issues'),
             duration: Duration(seconds: 10),
diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index 13cb688d37..a785fb78ba 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -56,7 +56,7 @@ class FlutterBuildState extends ChangeNotifier {
         Timer.periodic(refreshRate, (_) => _fetchBuildStatusUpdate());
   }
 
-  /// Request the latest [statuses] from [CocoonService].
+  /// Request the latest [statuses] and [isTreeBuilding] from [CocoonService].
   Future<void> _fetchBuildStatusUpdate() async {
     await Future.wait(<Future<void>>[
       _cocoonService.fetchCommitStatuses().then(
@@ -84,10 +84,13 @@ class FlutterBuildState extends ChangeNotifier {
   }
 }
 
-/// Wrapper class for data in this state.
+/// Wrapper class for data this state serves.
 ///
-/// Holds [data] and information for errors.
+/// Holds [data] and possible error information.
 class CocoonResponse<T> {
+  /// The data that gets used from [CocoonService].
   T data;
+
+  /// Error information that can be used for debugging.
   String error;
 }
diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index 97c7658394..190be21362 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -21,7 +21,6 @@ class StatusGridContainer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final ThemeData theme = Theme.of(context);
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
         final CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;

From 3ac867de94bcb1b378a787193a6a469a2f46a973 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 11:17:06 -0700
Subject: [PATCH 05/17] simplified status grid statuses

---
 app_flutter/lib/status_grid.dart | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index 190be21362..0cc222cef5 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -23,10 +23,10 @@ class StatusGridContainer extends StatelessWidget {
   Widget build(BuildContext context) {
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
-        final CocoonResponse<List<CommitStatus>> statuses = buildState.statuses;
+        final List<CommitStatus> statuses = buildState.statuses.data;
 
         // Assume if there is no data that it is loading.
-        if (statuses.data.isEmpty) {
+        if (statuses.isEmpty) {
           return const Expanded(
             child: Center(
               child: CircularProgressIndicator(),
@@ -35,7 +35,7 @@ class StatusGridContainer extends StatelessWidget {
         }
 
         return StatusGrid(
-          statuses: statuses.data,
+          statuses: statuses,
         );
       },
     );

From e2c72468965af5c7b72de7d814e9c489cd80f996 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 13:50:52 -0700
Subject: [PATCH 06/17] added test for setting error in CocoonResponse

---
 .../test/state/flutter_build_test.dart        | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/app_flutter/test/state/flutter_build_test.dart b/app_flutter/test/state/flutter_build_test.dart
index 3f83f129b9..f5ce6bdafc 100644
--- a/app_flutter/test/state/flutter_build_test.dart
+++ b/app_flutter/test/state/flutter_build_test.dart
@@ -60,6 +60,35 @@ void main() {
       // Tear down fails to cancel the timer before the test is over
       buildState.dispose();
     });
+
+    testWidgets('error when fetching statuses should be set in CocoonResponse',
+        (WidgetTester tester) async {
+      when(mockService.fetchCommitStatuses())
+          .thenAnswer((_) => Future<List<CommitStatus>>.error(42));
+
+      buildState.startFetchingBuildStateUpdates();
+
+      await tester.pumpAndSettle();
+
+      expect(buildState.statuses.error, isNotNull);
+
+      buildState.dispose();
+    });
+
+    testWidgets(
+        'error when fetching tree build status should be set in CocoonResponse',
+        (WidgetTester tester) async {
+      when(mockService.fetchTreeBuildStatus())
+          .thenAnswer((_) => Future<bool>.error(42));
+
+      buildState.startFetchingBuildStateUpdates();
+
+      await tester.pumpAndSettle();
+
+      expect(buildState.isTreeBuilding.error, isNotNull);
+
+      buildState.dispose();
+    });
   });
 }
 

From 8375553640f77801485b9ab53e84c67aeda1c0e8 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 13:55:45 -0700
Subject: [PATCH 07/17] tested hasError

---
 app_flutter/lib/state/flutter_build.dart       | 2 +-
 app_flutter/test/state/flutter_build_test.dart | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index a785fb78ba..9ce579a65d 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -40,7 +40,7 @@ class FlutterBuildState extends ChangeNotifier {
   CocoonResponse<bool> get isTreeBuilding => _isTreeBuilding;
 
   /// Whether an error occured getting the latest data for the fields of this state.
-  bool get hasError => _isTreeBuilding.error ?? _statuses.error ?? false;
+  bool get hasError => _isTreeBuilding != null || _statuses.error != null;
 
   /// Start a fixed interval loop that fetches build state updates based on [refreshRate].
   Future<void> startFetchingBuildStateUpdates() async {
diff --git a/app_flutter/test/state/flutter_build_test.dart b/app_flutter/test/state/flutter_build_test.dart
index f5ce6bdafc..6b72bd9a82 100644
--- a/app_flutter/test/state/flutter_build_test.dart
+++ b/app_flutter/test/state/flutter_build_test.dart
@@ -70,6 +70,7 @@ void main() {
 
       await tester.pumpAndSettle();
 
+      expect(buildState.hasError, true);
       expect(buildState.statuses.error, isNotNull);
 
       buildState.dispose();
@@ -85,6 +86,7 @@ void main() {
 
       await tester.pumpAndSettle();
 
+      expect(buildState.hasError, true);
       expect(buildState.isTreeBuilding.error, isNotNull);
 
       buildState.dispose();

From f942ace942accbd290db270ac9ac6ab5f8b75ef4 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 14:51:21 -0700
Subject: [PATCH 08/17] working on seeing if BuildDashboard handles error

---
 app_flutter/lib/state/flutter_build.dart   |  2 +-
 app_flutter/test/build_dashboard_test.dart | 48 ++++++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 app_flutter/test/build_dashboard_test.dart

diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index 9ce579a65d..ae31a57705 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -40,7 +40,7 @@ class FlutterBuildState extends ChangeNotifier {
   CocoonResponse<bool> get isTreeBuilding => _isTreeBuilding;
 
   /// Whether an error occured getting the latest data for the fields of this state.
-  bool get hasError => _isTreeBuilding != null || _statuses.error != null;
+  bool get hasError => _isTreeBuilding.error != null || _statuses.error != null;
 
   /// Start a fixed interval loop that fetches build state updates based on [refreshRate].
   Future<void> startFetchingBuildStateUpdates() async {
diff --git a/app_flutter/test/build_dashboard_test.dart b/app_flutter/test/build_dashboard_test.dart
new file mode 100644
index 0000000000..3610b95a84
--- /dev/null
+++ b/app_flutter/test/build_dashboard_test.dart
@@ -0,0 +1,48 @@
+// Copyright (c) 2019 The Chromium Authors. 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/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+import 'package:provider/provider.dart';
+
+import 'package:cocoon_service/protos.dart' show CommitStatus;
+
+import 'package:app_flutter/build_dashboard.dart';
+import 'package:app_flutter/state/flutter_build.dart';
+
+void main() {
+  group('BuildDashboard', () {
+    testWidgets('should show error when FlutterBuildState has error',
+        (WidgetTester tester) async {
+      final MockFlutterBuildState buildState = MockFlutterBuildState();
+
+      when(buildState.hasError).thenReturn(true);
+      when(buildState.statuses).thenReturn(
+          CocoonResponse<List<CommitStatus>>()..error = 'status error');
+      when(buildState.isTreeBuilding)
+          .thenReturn(CocoonResponse<bool>()..data = false);
+
+      buildState.startFetchingBuildStateUpdates();
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: ChangeNotifierProvider<FlutterBuildState>(
+            builder: (_) => buildState,
+            child: BuildDashboard(),
+          ),
+        ),
+      );
+
+      await tester.pump(const Duration(seconds: 1));
+
+      expect(find.text('Cocoon Backend is having issues'), findsOneWidget);
+
+      buildState.dispose();
+    });
+  });
+}
+
+/// [FlutterBuildState] for giving errors.
+class MockFlutterBuildState extends Mock implements FlutterBuildState {}

From 3f8390a823971e546b85e9b502742e18707272d7 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Fri, 4 Oct 2019 15:42:19 -0700
Subject: [PATCH 09/17] it aint much but its honest work

---
 app_flutter/test/build_dashboard_test.dart | 1 +
 1 file changed, 1 insertion(+)

diff --git a/app_flutter/test/build_dashboard_test.dart b/app_flutter/test/build_dashboard_test.dart
index 3610b95a84..3f0cd8f154 100644
--- a/app_flutter/test/build_dashboard_test.dart
+++ b/app_flutter/test/build_dashboard_test.dart
@@ -36,6 +36,7 @@ void main() {
       );
 
       await tester.pump(const Duration(seconds: 1));
+      await tester.pump();
 
       expect(find.text('Cocoon Backend is having issues'), findsOneWidget);
 

From 442c6206c9bd37e4a16852744579bc2776797d4d Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 10:58:04 -0700
Subject: [PATCH 10/17] made error message a variable

---
 app_flutter/lib/build_dashboard.dart       |  5 ++++-
 app_flutter/test/build_dashboard_test.dart | 22 ++++++++++++----------
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/app_flutter/lib/build_dashboard.dart b/app_flutter/lib/build_dashboard.dart
index e0c2a14bf0..1e9ec11743 100644
--- a/app_flutter/lib/build_dashboard.dart
+++ b/app_flutter/lib/build_dashboard.dart
@@ -42,6 +42,9 @@ class _BuildDashboardPageState extends State<BuildDashboardPage> {
 /// The tree's current build status is reflected in the color of [AppBar].
 /// The results from tasks run on individual commits is shown in [StatusGrid].
 class BuildDashboard extends StatelessWidget {
+  @visibleForTesting
+  static const String errorCocoonBackend = 'Cocoon Backend is having issues';
+
   @override
   Widget build(BuildContext context) {
     final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
@@ -55,7 +58,7 @@ class BuildDashboard extends StatelessWidget {
 
           // TODO(chillers): Make this display better on the TV by using a bigger widget.
           const SnackBar snackbar = SnackBar(
-            content: Text('Cocoon Backend is having issues'),
+            content: Text(errorCocoonBackend),
             duration: Duration(seconds: 10),
             behavior: SnackBarBehavior.floating,
           );
diff --git a/app_flutter/test/build_dashboard_test.dart b/app_flutter/test/build_dashboard_test.dart
index 3f0cd8f154..5cd9898bb9 100644
--- a/app_flutter/test/build_dashboard_test.dart
+++ b/app_flutter/test/build_dashboard_test.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:app_flutter/service/fake_cocoon.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/mockito.dart';
@@ -16,13 +17,15 @@ void main() {
   group('BuildDashboard', () {
     testWidgets('should show error when FlutterBuildState has error',
         (WidgetTester tester) async {
-      final MockFlutterBuildState buildState = MockFlutterBuildState();
+      final MockCocoonService errorService = MockCocoonService();
 
-      when(buildState.hasError).thenReturn(true);
-      when(buildState.statuses).thenReturn(
-          CocoonResponse<List<CommitStatus>>()..error = 'status error');
-      when(buildState.isTreeBuilding)
-          .thenReturn(CocoonResponse<bool>()..data = false);
+      when(errorService.fetchCommitStatuses())
+          .thenAnswer((_) => Future<List<CommitStatus>>.error(0));
+      when(errorService.fetchTreeBuildStatus())
+          .thenAnswer((_) => Future<bool>.value(false));
+
+      final FlutterBuildState buildState =
+          FlutterBuildState(cocoonService: errorService);
 
       buildState.startFetchingBuildStateUpdates();
 
@@ -35,15 +38,14 @@ void main() {
         ),
       );
 
-      await tester.pump(const Duration(seconds: 1));
       await tester.pump();
 
-      expect(find.text('Cocoon Backend is having issues'), findsOneWidget);
+      expect(find.text(BuildDashboard.errorCocoonBackend), findsOneWidget);
 
       buildState.dispose();
     });
   });
 }
 
-/// [FlutterBuildState] for giving errors.
-class MockFlutterBuildState extends Mock implements FlutterBuildState {}
+/// [FakeCocoonService] for giving errors.
+class MockCocoonService extends Mock implements FakeCocoonService {}

From ccecf0a11c5d5cab463d3d568d36edafb3ba8bb4 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 11:27:29 -0700
Subject: [PATCH 11/17] moved flutterbuildstate error snackbar down a level

---
 app_flutter/lib/build_dashboard.dart       | 19 --------
 app_flutter/lib/status_grid.dart           | 18 ++++++++
 app_flutter/test/build_dashboard_test.dart | 51 ----------------------
 app_flutter/test/status_grid_test.dart     | 29 ++++++++++++
 4 files changed, 47 insertions(+), 70 deletions(-)
 delete mode 100644 app_flutter/test/build_dashboard_test.dart

diff --git a/app_flutter/lib/build_dashboard.dart b/app_flutter/lib/build_dashboard.dart
index 1e9ec11743..3eb8978098 100644
--- a/app_flutter/lib/build_dashboard.dart
+++ b/app_flutter/lib/build_dashboard.dart
@@ -42,31 +42,12 @@ class _BuildDashboardPageState extends State<BuildDashboardPage> {
 /// The tree's current build status is reflected in the color of [AppBar].
 /// The results from tasks run on individual commits is shown in [StatusGrid].
 class BuildDashboard extends StatelessWidget {
-  @visibleForTesting
-  static const String errorCocoonBackend = 'Cocoon Backend is having issues';
-
   @override
   Widget build(BuildContext context) {
-    final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
     final ThemeData theme = Theme.of(context);
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
-        if (buildState.hasError) {
-          print('FlutterBuildState has an error');
-          print('isTreeBuilding: ${buildState.isTreeBuilding.error}');
-          print('statuses: ${buildState.statuses.error}');
-
-          // TODO(chillers): Make this display better on the TV by using a bigger widget.
-          const SnackBar snackbar = SnackBar(
-            content: Text(errorCocoonBackend),
-            duration: Duration(seconds: 10),
-            behavior: SnackBarBehavior.floating,
-          );
-          _scaffoldKey.currentState.showSnackBar(snackbar);
-        }
-
         return Scaffold(
-          key: _scaffoldKey,
           appBar: AppBar(
             title: const Text('Flutter Build Dashboard v2'),
             backgroundColor: buildState.isTreeBuilding.data
diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index 0cc222cef5..a8e2f9e4ce 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -16,15 +16,33 @@ import 'task_icon.dart';
 /// Container that manages the layout and data handling for [StatusGrid].
 ///
 /// If there's no data for [StatusGrid], it shows [CircularProgressIndicator].
+/// If [FlutterBuildState] had an error, it shows [Snackbar] stating there are issues.
 class StatusGridContainer extends StatelessWidget {
   const StatusGridContainer({Key key}) : super(key: key);
 
+  @visibleForTesting
+  static const String errorCocoonBackend = 'Cocoon Backend is having issues';
+
   @override
   Widget build(BuildContext context) {
     return Consumer<FlutterBuildState>(
       builder: (_, FlutterBuildState buildState, Widget child) {
         final List<CommitStatus> statuses = buildState.statuses.data;
 
+        if (buildState.hasError) {
+          print('FlutterBuildState has an error');
+          print('isTreeBuilding: ${buildState.isTreeBuilding.error}');
+          print('statuses: ${buildState.statuses.error}');
+
+          // TODO(chillers): Make this display better on the TV by using a bigger widget.
+          const SnackBar snackbar = SnackBar(
+            content: Text(errorCocoonBackend),
+            duration: Duration(seconds: 10),
+            behavior: SnackBarBehavior.floating,
+          );
+          Scaffold.of(context).showSnackBar(snackbar);
+        }
+
         // Assume if there is no data that it is loading.
         if (statuses.isEmpty) {
           return const Expanded(
diff --git a/app_flutter/test/build_dashboard_test.dart b/app_flutter/test/build_dashboard_test.dart
deleted file mode 100644
index 5cd9898bb9..0000000000
--- a/app_flutter/test/build_dashboard_test.dart
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright (c) 2019 The Chromium Authors. 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:app_flutter/service/fake_cocoon.dart';
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
-import 'package:provider/provider.dart';
-
-import 'package:cocoon_service/protos.dart' show CommitStatus;
-
-import 'package:app_flutter/build_dashboard.dart';
-import 'package:app_flutter/state/flutter_build.dart';
-
-void main() {
-  group('BuildDashboard', () {
-    testWidgets('should show error when FlutterBuildState has error',
-        (WidgetTester tester) async {
-      final MockCocoonService errorService = MockCocoonService();
-
-      when(errorService.fetchCommitStatuses())
-          .thenAnswer((_) => Future<List<CommitStatus>>.error(0));
-      when(errorService.fetchTreeBuildStatus())
-          .thenAnswer((_) => Future<bool>.value(false));
-
-      final FlutterBuildState buildState =
-          FlutterBuildState(cocoonService: errorService);
-
-      buildState.startFetchingBuildStateUpdates();
-
-      await tester.pumpWidget(
-        MaterialApp(
-          home: ChangeNotifierProvider<FlutterBuildState>(
-            builder: (_) => buildState,
-            child: BuildDashboard(),
-          ),
-        ),
-      );
-
-      await tester.pump();
-
-      expect(find.text(BuildDashboard.errorCocoonBackend), findsOneWidget);
-
-      buildState.dispose();
-    });
-  });
-}
-
-/// [FakeCocoonService] for giving errors.
-class MockCocoonService extends Mock implements FakeCocoonService {}
diff --git a/app_flutter/test/status_grid_test.dart b/app_flutter/test/status_grid_test.dart
index 213052dc62..37b3232fc2 100644
--- a/app_flutter/test/status_grid_test.dart
+++ b/app_flutter/test/status_grid_test.dart
@@ -4,6 +4,7 @@
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
 import 'package:provider/provider.dart';
 
 import 'package:cocoon_service/protos.dart' show CommitStatus, Task;
@@ -104,5 +105,33 @@ void main() {
 
       expect(lastTaskWidget.task, lastTask);
     });
+
+    testWidgets('shows error message when FlutterBuildState has error',
+        (WidgetTester tester) async {
+      final MockFlutterBuildState buildState = MockFlutterBuildState();
+
+      when(buildState.hasError).thenReturn(true);
+      when(buildState.statuses)
+          .thenReturn(CocoonResponse<List<CommitStatus>>()..error = 'error!');
+      when(buildState.isTreeBuilding)
+          .thenReturn(CocoonResponse<bool>()..data = false);
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: ChangeNotifierProvider<FlutterBuildState>(
+              builder: (_) => buildState,
+              child: const StatusGridContainer(),
+            ),
+          ),
+        ),
+      );
+
+      await tester.pump();
+
+      expect(find.text(StatusGridContainer.errorCocoonBackend), findsOneWidget);
+    });
   });
 }
+
+class MockFlutterBuildState extends Mock implements FlutterBuildState {}

From 63abd2837b71916d1406d997efe456729997d59d Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 11:48:05 -0700
Subject: [PATCH 12/17] print appengine error responses

---
 app_flutter/lib/service/appengine_cocoon.dart | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/app_flutter/lib/service/appengine_cocoon.dart b/app_flutter/lib/service/appengine_cocoon.dart
index f5d69c67c6..a3d4f4223d 100644
--- a/app_flutter/lib/service/appengine_cocoon.dart
+++ b/app_flutter/lib/service/appengine_cocoon.dart
@@ -37,6 +37,7 @@ class AppEngineCocoonService implements CocoonService {
         await _client.get('$_baseApiUrl/public/get-status');
 
     if (response.statusCode != HttpStatus.ok) {
+      print(response);
       throw HttpException(
           '$_baseApiUrl/public/get-status returned ${response.statusCode}');
     }
@@ -53,6 +54,7 @@ class AppEngineCocoonService implements CocoonService {
         await _client.get('$_baseApiUrl/public/build-status');
 
     if (response.statusCode != HttpStatus.ok) {
+      print(response);
       throw HttpException(
           '$_baseApiUrl/public/build-status returned ${response.statusCode}');
     }

From ee1ce537637c6ad453291506ebae829245c90166 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 12:09:22 -0700
Subject: [PATCH 13/17] todo ui

---
 app_flutter/lib/status_grid.dart       |  8 +-------
 app_flutter/test/status_grid_test.dart | 28 --------------------------
 2 files changed, 1 insertion(+), 35 deletions(-)

diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index a8e2f9e4ce..03cbc0eead 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -34,13 +34,7 @@ class StatusGridContainer extends StatelessWidget {
           print('isTreeBuilding: ${buildState.isTreeBuilding.error}');
           print('statuses: ${buildState.statuses.error}');
 
-          // TODO(chillers): Make this display better on the TV by using a bigger widget.
-          const SnackBar snackbar = SnackBar(
-            content: Text(errorCocoonBackend),
-            duration: Duration(seconds: 10),
-            behavior: SnackBarBehavior.floating,
-          );
-          Scaffold.of(context).showSnackBar(snackbar);
+          // TODO(chillers): Display the error
         }
 
         // Assume if there is no data that it is loading.
diff --git a/app_flutter/test/status_grid_test.dart b/app_flutter/test/status_grid_test.dart
index 37b3232fc2..16b0f6f175 100644
--- a/app_flutter/test/status_grid_test.dart
+++ b/app_flutter/test/status_grid_test.dart
@@ -105,33 +105,5 @@ void main() {
 
       expect(lastTaskWidget.task, lastTask);
     });
-
-    testWidgets('shows error message when FlutterBuildState has error',
-        (WidgetTester tester) async {
-      final MockFlutterBuildState buildState = MockFlutterBuildState();
-
-      when(buildState.hasError).thenReturn(true);
-      when(buildState.statuses)
-          .thenReturn(CocoonResponse<List<CommitStatus>>()..error = 'error!');
-      when(buildState.isTreeBuilding)
-          .thenReturn(CocoonResponse<bool>()..data = false);
-
-      await tester.pumpWidget(
-        MaterialApp(
-          home: Scaffold(
-            body: ChangeNotifierProvider<FlutterBuildState>(
-              builder: (_) => buildState,
-              child: const StatusGridContainer(),
-            ),
-          ),
-        ),
-      );
-
-      await tester.pump();
-
-      expect(find.text(StatusGridContainer.errorCocoonBackend), findsOneWidget);
-    });
   });
 }
-
-class MockFlutterBuildState extends Mock implements FlutterBuildState {}

From 576a0407b60d926d73b7bb81bfb17443098b23d5 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 12:10:56 -0700
Subject: [PATCH 14/17] revert

---
 app_flutter/lib/build_dashboard.dart | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/app_flutter/lib/build_dashboard.dart b/app_flutter/lib/build_dashboard.dart
index 3eb8978098..0b038a325e 100644
--- a/app_flutter/lib/build_dashboard.dart
+++ b/app_flutter/lib/build_dashboard.dart
@@ -46,21 +46,19 @@ class BuildDashboard extends StatelessWidget {
   Widget build(BuildContext context) {
     final ThemeData theme = Theme.of(context);
     return Consumer<FlutterBuildState>(
-      builder: (_, FlutterBuildState buildState, Widget child) {
-        return Scaffold(
-          appBar: AppBar(
-            title: const Text('Flutter Build Dashboard v2'),
-            backgroundColor: buildState.isTreeBuilding.data
-                ? theme.primaryColor
-                : theme.errorColor,
-          ),
-          body: Column(
-            children: const <Widget>[
-              StatusGridContainer(),
-            ],
-          ),
-        );
-      },
+      builder: (_, FlutterBuildState buildState, Widget child) => Scaffold(
+        appBar: AppBar(
+          title: const Text('Flutter Build Dashboard v2'),
+          backgroundColor: buildState.isTreeBuilding.data
+              ? theme.primaryColor
+              : theme.errorColor,
+        ),
+        body: Column(
+          children: const <Widget>[
+            StatusGridContainer(),
+          ],
+        ),
+      ),
     );
   }
 }

From 9c883cedeae78b0e05df2e183d4c5687b9ad2ab9 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 12:12:16 -0700
Subject: [PATCH 15/17] removed documentaiton on ui that was not implemented

---
 app_flutter/lib/status_grid.dart | 1 -
 1 file changed, 1 deletion(-)

diff --git a/app_flutter/lib/status_grid.dart b/app_flutter/lib/status_grid.dart
index 03cbc0eead..ab9c789d91 100644
--- a/app_flutter/lib/status_grid.dart
+++ b/app_flutter/lib/status_grid.dart
@@ -16,7 +16,6 @@ import 'task_icon.dart';
 /// Container that manages the layout and data handling for [StatusGrid].
 ///
 /// If there's no data for [StatusGrid], it shows [CircularProgressIndicator].
-/// If [FlutterBuildState] had an error, it shows [Snackbar] stating there are issues.
 class StatusGridContainer extends StatelessWidget {
   const StatusGridContainer({Key key}) : super(key: key);
 

From 96cd4d16c02d3f9d06a0f1aaa2bdfe2f681f5716 Mon Sep 17 00:00:00 2001
From: Casey Hillers <chillers@google.com>
Date: Mon, 7 Oct 2019 12:13:09 -0700
Subject: [PATCH 16/17] removed old dep

---
 app_flutter/test/status_grid_test.dart | 1 -
 1 file changed, 1 deletion(-)

diff --git a/app_flutter/test/status_grid_test.dart b/app_flutter/test/status_grid_test.dart
index 16b0f6f175..213052dc62 100644
--- a/app_flutter/test/status_grid_test.dart
+++ b/app_flutter/test/status_grid_test.dart
@@ -4,7 +4,6 @@
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
 import 'package:provider/provider.dart';
 
 import 'package:cocoon_service/protos.dart' show CommitStatus, Task;

From 4ad8da9115b8e72602fbd657d903f85bc91cd950 Mon Sep 17 00:00:00 2001
From: Casey Hillers <caseyhillers@gmail.com>
Date: Tue, 8 Oct 2019 06:59:57 -0700
Subject: [PATCH 17/17] moved cocoonresponse into cocoonservice

---
 app_flutter/lib/service/appengine_cocoon.dart | 43 +++++++++-----
 app_flutter/lib/service/cocoon.dart           | 15 ++++-
 app_flutter/lib/service/fake_cocoon.dart      |  9 +--
 app_flutter/lib/state/flutter_build.dart      | 33 +++--------
 .../test/service/appengine_cocoon_test.dart   | 58 ++++++++++++-------
 .../test/state/flutter_build_test.dart        | 42 +++-----------
 app_flutter/test/status_grid_test.dart        |  5 +-
 7 files changed, 100 insertions(+), 105 deletions(-)

diff --git a/app_flutter/lib/service/appengine_cocoon.dart b/app_flutter/lib/service/appengine_cocoon.dart
index a3d4f4223d..7583918aeb 100644
--- a/app_flutter/lib/service/appengine_cocoon.dart
+++ b/app_flutter/lib/service/appengine_cocoon.dart
@@ -31,42 +31,55 @@ class AppEngineCocoonService implements CocoonService {
   final http.Client _client;
 
   @override
-  Future<List<CommitStatus>> fetchCommitStatuses() async {
+  Future<CocoonResponse<List<CommitStatus>>> fetchCommitStatuses() async {
     /// This endpoint returns JSON [List<Agent>, List<CommitStatus>]
     final http.Response response =
         await _client.get('$_baseApiUrl/public/get-status');
 
     if (response.statusCode != HttpStatus.ok) {
-      print(response);
-      throw HttpException(
-          '$_baseApiUrl/public/get-status returned ${response.statusCode}');
+      print(response.body);
+      return CocoonResponse<List<CommitStatus>>()
+        ..error =
+            '$_baseApiUrl/public/get-status returned ${response.statusCode}';
     }
 
-    final Map<String, Object> jsonResponse = jsonDecode(response.body);
-
-    return _commitStatusesFromJson(jsonResponse['Statuses']);
+    try {
+      final Map<String, Object> jsonResponse = jsonDecode(response.body);
+      return CocoonResponse<List<CommitStatus>>()
+        ..data = _commitStatusesFromJson(jsonResponse['Statuses']);
+    } catch (error) {
+      return CocoonResponse<List<CommitStatus>>()..error = error.toString();
+    }
   }
 
   @override
-  Future<bool> fetchTreeBuildStatus() async {
+  Future<CocoonResponse<bool>> fetchTreeBuildStatus() async {
     /// This endpoint returns JSON {AnticipatedBuildStatus: [BuildStatus]}
     final http.Response response =
         await _client.get('$_baseApiUrl/public/build-status');
 
     if (response.statusCode != HttpStatus.ok) {
-      print(response);
-      throw HttpException(
-          '$_baseApiUrl/public/build-status returned ${response.statusCode}');
+      print(response.body);
+      return CocoonResponse<bool>()
+        ..error =
+            '$_baseApiUrl/public/build-status returned ${response.statusCode}';
     }
 
-    final Map<String, Object> jsonResponse = jsonDecode(response.body);
+    Map<String, Object> jsonResponse;
+    try {
+      jsonResponse = jsonDecode(response.body);
+    } catch (error) {
+      return CocoonResponse<bool>()
+        ..error = '$_baseApiUrl/public/build-status had a malformed response';
+    }
 
     if (!_isBuildStatusResponseValid(jsonResponse)) {
-      throw const HttpException(
-          '$_baseApiUrl/public/build-status had a malformed response');
+      return CocoonResponse<bool>()
+        ..error = '$_baseApiUrl/public/build-status had a malformed response';
     }
 
-    return jsonResponse['AnticipatedBuildStatus'] == 'Succeeded';
+    return CocoonResponse<bool>()
+      ..data = jsonResponse['AnticipatedBuildStatus'] == 'Succeeded';
   }
 
   /// Check if [Map<String,Object>] follows the format for build-status.
diff --git a/app_flutter/lib/service/cocoon.dart b/app_flutter/lib/service/cocoon.dart
index c11e8debc8..7ca9523c23 100644
--- a/app_flutter/lib/service/cocoon.dart
+++ b/app_flutter/lib/service/cocoon.dart
@@ -30,8 +30,19 @@ abstract class CocoonService {
   /// Gets build information from the last 200 commits.
   ///
   // TODO(chillers): Make configurable to get range of commits, https://github.com/flutter/cocoon/issues/458
-  Future<List<CommitStatus>> fetchCommitStatuses();
+  Future<CocoonResponse<List<CommitStatus>>> fetchCommitStatuses();
 
   /// Gets the current build status of flutter/flutter.
-  Future<bool> fetchTreeBuildStatus();
+  Future<CocoonResponse<bool>> fetchTreeBuildStatus();
+}
+
+/// Wrapper class for data this state serves.
+///
+/// Holds [data] and possible error information.
+class CocoonResponse<T> {
+  /// The data that gets used from [CocoonService].
+  T data;
+
+  /// Error information that can be used for debugging.
+  String error;
 }
diff --git a/app_flutter/lib/service/fake_cocoon.dart b/app_flutter/lib/service/fake_cocoon.dart
index 7f2e9d68cd..474bd84dea 100644
--- a/app_flutter/lib/service/fake_cocoon.dart
+++ b/app_flutter/lib/service/fake_cocoon.dart
@@ -20,13 +20,14 @@ class FakeCocoonService implements CocoonService {
   final Random random;
 
   @override
-  Future<List<CommitStatus>> fetchCommitStatuses() async {
-    return _createFakeCommitStatuses();
+  Future<CocoonResponse<List<CommitStatus>>> fetchCommitStatuses() async {
+    return CocoonResponse<List<CommitStatus>>()
+      ..data = _createFakeCommitStatuses();
   }
 
   @override
-  Future<bool> fetchTreeBuildStatus() async {
-    return random.nextBool();
+  Future<CocoonResponse<bool>> fetchTreeBuildStatus() async {
+    return CocoonResponse<bool>()..data = random.nextBool();
   }
 
   List<CommitStatus> _createFakeCommitStatuses() {
diff --git a/app_flutter/lib/state/flutter_build.dart b/app_flutter/lib/state/flutter_build.dart
index ae31a57705..7d29843a23 100644
--- a/app_flutter/lib/state/flutter_build.dart
+++ b/app_flutter/lib/state/flutter_build.dart
@@ -30,13 +30,12 @@ class FlutterBuildState extends ChangeNotifier {
   Timer refreshTimer;
 
   /// The current status of the commits loaded.
-  final CocoonResponse<List<CommitStatus>> _statuses =
+  CocoonResponse<List<CommitStatus>> _statuses =
       CocoonResponse<List<CommitStatus>>()..data = <CommitStatus>[];
   CocoonResponse<List<CommitStatus>> get statuses => _statuses;
 
   /// Whether or not flutter/flutter currently passes tests.
-  final CocoonResponse<bool> _isTreeBuilding = CocoonResponse<bool>()
-    ..data = false;
+  CocoonResponse<bool> _isTreeBuilding = CocoonResponse<bool>()..data = false;
   CocoonResponse<bool> get isTreeBuilding => _isTreeBuilding;
 
   /// Whether an error occured getting the latest data for the fields of this state.
@@ -60,18 +59,11 @@ class FlutterBuildState extends ChangeNotifier {
   Future<void> _fetchBuildStatusUpdate() async {
     await Future.wait(<Future<void>>[
       _cocoonService.fetchCommitStatuses().then(
-          (List<CommitStatus> commitStatuses) {
-        _statuses.data = commitStatuses;
-        _statuses.error = null;
-      }, onError: (dynamic error) {
-        _statuses.error = error.toString();
-      }),
-      _cocoonService.fetchTreeBuildStatus().then((bool treeStatus) {
-        _isTreeBuilding.data = treeStatus;
-        _isTreeBuilding.error = null;
-      }, onError: (dynamic error) {
-        _isTreeBuilding.error = error.toString();
-      }),
+          (CocoonResponse<List<CommitStatus>> response) =>
+              _statuses = response),
+      _cocoonService
+          .fetchTreeBuildStatus()
+          .then((CocoonResponse<bool> response) => _isTreeBuilding = response),
     ]);
 
     notifyListeners();
@@ -83,14 +75,3 @@ class FlutterBuildState extends ChangeNotifier {
     super.dispose();
   }
 }
-
-/// Wrapper class for data this state serves.
-///
-/// Holds [data] and possible error information.
-class CocoonResponse<T> {
-  /// The data that gets used from [CocoonService].
-  T data;
-
-  /// Error information that can be used for debugging.
-  String error;
-}
diff --git a/app_flutter/test/service/appengine_cocoon_test.dart b/app_flutter/test/service/appengine_cocoon_test.dart
index de6e409d53..79c028a5ef 100644
--- a/app_flutter/test/service/appengine_cocoon_test.dart
+++ b/app_flutter/test/service/appengine_cocoon_test.dart
@@ -7,10 +7,12 @@ import 'package:http/http.dart' show Request, Response;
 import 'package:http/testing.dart';
 import 'package:test/test.dart';
 
-import 'package:app_flutter/service/appengine_cocoon.dart';
 import 'package:cocoon_service/protos.dart'
     show Commit, CommitStatus, Stage, Task;
 
+import 'package:app_flutter/service/appengine_cocoon.dart';
+import 'package:app_flutter/service/cocoon.dart';
+
 // This is based off data the Cocoon backend sends out from v1.
 // It doesn't map directly to protos since the backend does
 // not use protos yet.
@@ -86,13 +88,14 @@ void main() {
       }));
     });
 
-    test('should return List<CommitStatus>', () {
+    test('should return CocoonResponse<List<CommitStatus>>', () {
       expect(service.fetchCommitStatuses(),
-          const TypeMatcher<Future<List<CommitStatus>>>());
+          const TypeMatcher<Future<CocoonResponse<List<CommitStatus>>>>());
     });
 
     test('should return expected List<CommitStatus>', () async {
-      final List<CommitStatus> statuses = await service.fetchCommitStatuses();
+      final CocoonResponse<List<CommitStatus>> statuses =
+          await service.fetchCommitStatuses();
 
       final CommitStatus expectedStatus = CommitStatus()
         ..commit = (Commit()
@@ -118,22 +121,26 @@ void main() {
             ..stageName = 'devicelab'
             ..status = 'Succeeded'));
 
-      expect(statuses.length, 1);
-      expect(statuses.first, expectedStatus);
+      expect(statuses.data.length, 1);
+      expect(statuses.data.first, expectedStatus);
     });
 
-    test('should throw exception if given non-200 response', () {
+    test('should have error if given non-200 response', () async {
       service = AppEngineCocoonService(
           client: MockClient((Request request) async => Response('', 404)));
 
-      expect(service.fetchCommitStatuses(), throwsException);
+      final CocoonResponse<List<CommitStatus>> response =
+          await service.fetchCommitStatuses();
+      expect(response.error, isNotNull);
     });
 
-    test('should throw exception if given bad response', () {
+    test('should have error if given bad response', () async {
       service = AppEngineCocoonService(
           client: MockClient((Request request) async => Response('bad', 200)));
 
-      expect(service.fetchCommitStatuses(), throwsException);
+      final CocoonResponse<List<CommitStatus>> response =
+          await service.fetchCommitStatuses();
+      expect(response.error, isNotNull);
     });
   });
 
@@ -147,39 +154,46 @@ void main() {
       }));
     });
 
-    test('should return bool', () {
-      expect(service.fetchTreeBuildStatus(), const TypeMatcher<Future<bool>>());
+    test('should return CocoonResponse<bool>', () {
+      expect(service.fetchTreeBuildStatus(),
+          const TypeMatcher<Future<CocoonResponse<bool>>>());
     });
 
-    test('should return true when given Succeeded', () async {
-      final bool treeBuildStatus = await service.fetchTreeBuildStatus();
+    test('data should be true when given Succeeded', () async {
+      final CocoonResponse<bool> treeBuildStatus =
+          await service.fetchTreeBuildStatus();
 
-      expect(treeBuildStatus, true);
+      expect(treeBuildStatus.data, true);
     });
 
-    test('should return false when given Failed', () async {
+    test('data should be false when given Failed', () async {
       service =
           AppEngineCocoonService(client: MockClient((Request request) async {
         return Response(jsonBuildStatusFalseResponse, 200);
       }));
 
-      final bool treeBuildStatus = await service.fetchTreeBuildStatus();
+      final CocoonResponse<bool> treeBuildStatus =
+          await service.fetchTreeBuildStatus();
 
-      expect(treeBuildStatus, false);
+      expect(treeBuildStatus.data, false);
     });
 
-    test('should throw exception if given non-200 response', () {
+    test('should have error if given non-200 response', () async {
       service = AppEngineCocoonService(
           client: MockClient((Request request) async => Response('', 404)));
 
-      expect(service.fetchTreeBuildStatus(), throwsException);
+      final CocoonResponse<bool> response =
+          await service.fetchTreeBuildStatus();
+      expect(response.error, isNotNull);
     });
 
-    test('should throw exception if given bad response', () {
+    test('should have error if given bad response', () async {
       service = AppEngineCocoonService(
           client: MockClient((Request request) async => Response('bad', 200)));
 
-      expect(service.fetchTreeBuildStatus(), throwsException);
+      final CocoonResponse<bool> response =
+          await service.fetchTreeBuildStatus();
+      expect(response.error, isNotNull);
     });
   });
 }
diff --git a/app_flutter/test/state/flutter_build_test.dart b/app_flutter/test/state/flutter_build_test.dart
index 6b72bd9a82..dfa2b4fe10 100644
--- a/app_flutter/test/state/flutter_build_test.dart
+++ b/app_flutter/test/state/flutter_build_test.dart
@@ -9,6 +9,7 @@ import 'package:mockito/mockito.dart';
 
 import 'package:cocoon_service/protos.dart' show CommitStatus;
 
+import 'package:app_flutter/service/cocoon.dart';
 import 'package:app_flutter/service/fake_cocoon.dart';
 import 'package:app_flutter/state/flutter_build.dart';
 
@@ -21,10 +22,12 @@ void main() {
       mockService = MockCocoonService();
       buildState = FlutterBuildState(cocoonService: mockService);
 
-      when(mockService.fetchCommitStatuses()).thenAnswer(
-          (_) => Future<List<CommitStatus>>.value(<CommitStatus>[]));
-      when(mockService.fetchTreeBuildStatus())
-          .thenAnswer((_) => Future<bool>.value(true));
+      when(mockService.fetchCommitStatuses()).thenAnswer((_) =>
+          Future<CocoonResponse<List<CommitStatus>>>.value(
+              CocoonResponse<List<CommitStatus>>()..data = <CommitStatus>[]));
+      when(mockService.fetchTreeBuildStatus()).thenAnswer((_) =>
+          Future<CocoonResponse<bool>>.value(
+              CocoonResponse<bool>()..data = true));
     });
 
     testWidgets('timer should periodically fetch updates',
@@ -60,37 +63,6 @@ void main() {
       // Tear down fails to cancel the timer before the test is over
       buildState.dispose();
     });
-
-    testWidgets('error when fetching statuses should be set in CocoonResponse',
-        (WidgetTester tester) async {
-      when(mockService.fetchCommitStatuses())
-          .thenAnswer((_) => Future<List<CommitStatus>>.error(42));
-
-      buildState.startFetchingBuildStateUpdates();
-
-      await tester.pumpAndSettle();
-
-      expect(buildState.hasError, true);
-      expect(buildState.statuses.error, isNotNull);
-
-      buildState.dispose();
-    });
-
-    testWidgets(
-        'error when fetching tree build status should be set in CocoonResponse',
-        (WidgetTester tester) async {
-      when(mockService.fetchTreeBuildStatus())
-          .thenAnswer((_) => Future<bool>.error(42));
-
-      buildState.startFetchingBuildStateUpdates();
-
-      await tester.pumpAndSettle();
-
-      expect(buildState.hasError, true);
-      expect(buildState.isTreeBuilding.error, isNotNull);
-
-      buildState.dispose();
-    });
   });
 }
 
diff --git a/app_flutter/test/status_grid_test.dart b/app_flutter/test/status_grid_test.dart
index 213052dc62..c65bd26aa3 100644
--- a/app_flutter/test/status_grid_test.dart
+++ b/app_flutter/test/status_grid_test.dart
@@ -8,6 +8,7 @@ import 'package:provider/provider.dart';
 
 import 'package:cocoon_service/protos.dart' show CommitStatus, Task;
 
+import 'package:app_flutter/service/cocoon.dart';
 import 'package:app_flutter/service/fake_cocoon.dart';
 import 'package:app_flutter/state/flutter_build.dart';
 import 'package:app_flutter/commit_box.dart';
@@ -20,7 +21,9 @@ void main() {
 
     setUpAll(() async {
       final FakeCocoonService service = FakeCocoonService();
-      statuses = await service.fetchCommitStatuses();
+      final CocoonResponse<List<CommitStatus>> response =
+          await service.fetchCommitStatuses();
+      statuses = response.data;
     });
 
     testWidgets('shows loading indicator when statuses is empty',