Added a test to ensure PlatformDispatcher and PlatformConfig have the same getters with exceptions.

Author: pdblasi-google

testing/dart/platform_dispatcher_test.dart

@@ -2,8 +2,13 @@
 // 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:ui';
 
+import 'package:analyzer/dart/analysis/features.dart';
+import 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/dart/analysis/utilities.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:litetest/litetest.dart';
 
 void main() {
@@ -39,4 +44,60 @@ void main() {
       return ViewConfiguration(view: view)..copyWith(view: view, window: view);
     });
   });
+
+  test("PlatformDispatcher and PlatformConfiguration have matching getters", () {
+      final List<Pattern> exclusionCriteria = <Pattern>[
+        RegExp(r'^_.*'), // exclude any private members
+        RegExp(r'^on[A-Z].*'), // exclude any callbacks
+        RegExp(r'locale$'), // locale is a convenience getter for interacting with `locales` which _is_ backed by the config
+        'instance', // exclude the static instance of PlatformDispatcher
+        'configuration', // the configuration should not reference itself
+        'views', // views are backed by their own config and don't need to be referenced in the platform config
+        'initialLifecycleState', // default route is stored/retrieved from the platform, not the engine
+        'frameData', // framed data updates too often and would kick off too many config changes
+      ];
+
+      final String flutterDir = Platform.environment['FLUTTER_DIR']!;
+      final List<ClassDeclaration> classes = parseFile(
+        path: '$flutterDir/lib/ui/platform_dispatcher.dart',
+        featureSet: FeatureSet.latestLanguageVersion(),
+        throwIfDiagnostics: false,
+      ).unit.declarations.whereType<ClassDeclaration>().toList();
+      final ClassDeclaration dispatcherClass = classes.singleWhere((ClassDeclaration c) => c.name.toString() == (PlatformDispatcher).toString());
+      final ClassDeclaration configurationClass = classes.singleWhere((ClassDeclaration c) => c.name.toString() == (PlatformConfiguration).toString());
+
+      Iterable<String> getNameOfClassMember(ClassMember member) {
+        if (member is MethodDeclaration) {
+          return <String>[member.name.toString()];
+        }else if (member is FieldDeclaration) {
+          return member.fields.variables.map((VariableDeclaration variable) => variable.name.toString());
+        } else {
+          return [];
+        }
+      }
+
+      final Set<String> dispatcherMembers = dispatcherClass.members
+        .where((ClassMember member) =>
+          member is FieldDeclaration ||
+          member is MethodDeclaration && member.isGetter)
+        .expand<String>(getNameOfClassMember)
+        .where((String name) =>
+          exclusionCriteria.every((criteria) =>
+            criteria.allMatches(name).isEmpty))
+        .toSet();
+      final Set<String> configurationMembers = configurationClass.members
+        .where((ClassMember member) =>
+          member is FieldDeclaration ||
+          member is MethodDeclaration && member.isGetter)
+        .expand(getNameOfClassMember)
+        .toSet();
+
+      final Set<String> missingMembers = configurationMembers.difference(dispatcherMembers);
+      final Set<String> extraMembers = dispatcherMembers.difference(configurationMembers);
+      expect(missingMembers.isEmpty && extraMembers.isEmpty, isTrue,
+        reason:
+          'PlatformDispatcher is out of sync with PlatformConfiguration.\n'
+          '  Missing Members: $missingMembers\n'
+          '  Members not backed by PlatformConfiguration: $extraMembers');
+  });
 }