Add golden_toolkit to sharezone_widgets (#900)

lib/sharezone_widgets/dart_test.yaml

@@ -0,0 +1,15 @@
+# Copyright (c) 2022 Sharezone UG (haftungsbeschränkt)
+# Licensed under the EUPL-1.2-or-later.
+#
+# You may obtain a copy of the Licence at:
+# https://joinup.ec.europa.eu/software/page/eupl
+#
+# SPDX-License-Identifier: EUPL-1.2
+
+tags:
+  # The tag "golden" is used by the "golden_toolkit" package.
+  #
+  # This will indicate that goldens are an expected test tag. All tests that use
+  # testGoldens() will automatically be given this tag. This allows you to
+  # easily target golden tests from the command line.
+  golden:

lib/sharezone_widgets/pubspec.lock

@@ -277,6 +277,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  golden_toolkit:
+    dependency: "direct dev"
+    description:
+      name: golden_toolkit
+      sha256: "8f74adab33154fe7b731395782797021f97d2edc52f7bfb85ff4f1b5c4a215f0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.15.0"
   http_parser:
     dependency: transitive
     description:

lib/sharezone_widgets/pubspec.yaml

@@ -35,5 +35,6 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  golden_toolkit: ^0.15.0
   sharezone_lints:
     path: ../sharezone_lints

lib/sharezone_widgets/test_goldens/flutter_test_config.dart

@@ -0,0 +1,46 @@
+// Copyright (c) 2022 Sharezone UG (haftungsbeschränkt)
+// Licensed under the EUPL-1.2-or-later.
+//
+// You may obtain a copy of the Licence at:
+// https://joinup.ec.europa.eu/software/page/eupl
+//
+// SPDX-License-Identifier: EUPL-1.2
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:ui';
+
+import 'package:golden_toolkit/golden_toolkit.dart';
+
+Future<void> testExecutable(FutureOr<void> Function() testMain) async {
+  const Device phoneLandscape = Device(
+    name: 'phone_landscape',
+    size: Size(667, 375),
+  );
+
+  return GoldenToolkit.runWithConfiguration(
+    () async {
+      await loadAppFonts();
+      await testMain();
+    },
+    config: GoldenToolkitConfiguration(
+      // Due to slight differences in rendering across platforms, mostly around
+      // text, the tests will only be run on a macOS machine on Github Actions.
+      // This means that if you update the tests on a Linux or Windows machine
+      // the golden tests will not pass on Github Actions. Instead you are
+      // recommended to download the goldens directly from the failed Github
+      // Actions job, and use those inside of your branch.
+      //
+      // See
+      // https://github.com/flutter/flutter/issues/36667#issuecomment-521335243.
+      skipGoldenAssertion: () => !Platform.isMacOS,
+      defaultDevices: const [
+        Device.phone,
+        phoneLandscape,
+        Device.tabletLandscape,
+        Device.tabletPortrait,
+        Device.iphone11,
+      ],
+    ),
+  );
+}