@ F r integrated Richard's solution (force)

.gitignore

@@ -17,5 +17,6 @@ generated_*
 
 # Other files
 .old.dart
+.build
 
 .DS_Store

lib/src/widget/src/common.dart

@@ -0,0 +1,17 @@
+import 'dart:io';
+
+const topBar = '▶▶▶▶';
+const bottomBar = '◀◀◀◀';
+
+/// [String] extension
+extension StringApprovedExtension on String {
+  /// git diff complains when file doesn't end in newline. This getter ensures a string does.
+  String get endWithNewline => endsWith('\n') ? this : '$this\n';
+}
+
+extension DirectoryApprovedExtension on Directory {
+  Set<File> filesWithExtension(String extension) {
+    final fileSystemEntities = listSync().where((entity) => entity is File && entity.path.endsWith(extension));
+    return fileSystemEntities.whereType<File>().toSet();
+  }
+}

lib/src/widget/src/get_widget_names.dart

@@ -0,0 +1,166 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:analyzer/dart/analysis/context_builder.dart';
+import 'package:analyzer/dart/analysis/context_locator.dart';
+import 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:approval_tests/src/widget/src/common.dart';
+
+final _widgetNamesDir = Directory('./test/approved');
+final _widgetNamesPath = '${_widgetNamesDir.path}/class_names.txt';
+
+Future<Set<String>> getWidgetNames() async {
+  final resultCompleter = Completer<Set<String>>();
+
+  await isWidgetNamesFileFresh().then((isFileFresh) {
+    if (isFileFresh) {
+      readWidgetsFile(_widgetNamesPath).then((widgetNames) {
+        resultCompleter.complete(widgetNames);
+      });
+    } else {
+      final libPath = '${Directory.current.absolute.path}/lib';
+      stdout.write("package:approved: searching for class names in $libPath...");
+      extractWidgetNames(libPath).then((widgetsList) {
+        if (!_widgetNamesDir.existsSync()) {
+          _widgetNamesDir.createSync();
+        }
+        _widgetNamesDir.createSync();
+        final widgetsFile = File(_widgetNamesPath);
+        widgetsFile.createSync();
+        const header = '''
+# This file was autogenerated by package:approved. Please do not edit.
+# Below is a list of class found in the project /lib folder.''';
+        final widgetNamesString = widgetsList.join('\n').endWithNewline;
+        widgetsFile.writeAsStringSync('$header\n$widgetNamesString');
+        stdout.write('done\n');
+        resultCompleter.complete(widgetsList);
+      });
+    }
+  });
+
+  return resultCompleter.future;
+}
+
+String loadWidgetNames() {
+  late String result;
+  final widgetNamesFile = File(_widgetNamesPath);
+  if (widgetNamesFile.existsSync()) {
+    result = widgetNamesFile.readAsStringSync();
+  }
+  return result;
+}
+
+/// Crawls the project and extracts widget names.
+Future<Set<String>> extractWidgetNames(String libPath) async {
+  final completer = Completer<Set<String>>();
+
+  final contextLocator = ContextLocator();
+  final contextRoots = contextLocator.locateRoots(includedPaths: [libPath]);
+
+  final contextBuilder = ContextBuilder();
+  await getFlutterSdkPath().then((path) {
+    final dartStr = '$path/bin/cache/dart-sdk';
+    final analysisContext = contextBuilder.createContext(
+      contextRoot: contextRoots.first,
+      sdkPath: dartStr,
+    );
+
+    final classNames = <String>{};
+
+    // Traverse all files in the lib folder
+    final libDirectory = Directory(libPath);
+    final dartFiles = libDirectory.listSync(recursive: true).where(
+          (file) =>
+              file.path.endsWith('.dart') && !file.path.contains('.g.dart') && !file.path.contains('.freezed.dart'),
+        );
+
+    for (final file in dartFiles) {
+      final analysisSession = analysisContext.currentSession;
+      final parsedResult = analysisSession.getParsedUnit(file.path) as ParsedUnitResult;
+
+      for (final compilationUnitMember in parsedResult.unit.declarations) {
+        if (compilationUnitMember is ClassDeclaration) {
+          final String name = compilationUnitMember.name.value().toString();
+          if (!name.startsWith('_')) {
+            classNames.add(name);
+          }
+        }
+      }
+    }
+
+    completer.complete(classNames);
+  });
+
+  return completer.future;
+}
+
+/// Get the path to the Flutter SDK
+Future<String> getFlutterSdkPath() async {
+  final completer = Completer<String>();
+
+  await Process.run('flutter', ['--version', '--machine']).then((result) {
+    if (result.exitCode != 0) {
+      throw Exception('Failed to run flutter command: ${result.stderr}');
+    }
+
+    final jsonData = jsonDecode(result.stdout.toString()) as Map<String, dynamic>;
+
+    completer.complete(jsonData['flutterRoot'].toString());
+  });
+
+  return completer.future;
+}
+
+Future<Set<String>> readWidgetsFile(String filePath) async {
+  final completer = Completer<Set<String>>();
+  final File file = File(filePath);
+
+  await file.readAsString().then((text) {
+    // Split by lines
+    final linesList = text.split('\n');
+    // Remove empty lines and comments
+    final linesSet = linesList.where((line) => line.isNotEmpty && !line.startsWith('#')).toSet();
+    completer.complete(linesSet);
+  });
+
+  return completer.future;
+}
+
+Future<bool> isWidgetNamesFileFresh() async {
+  final resultCompleter = Completer<bool>();
+
+  final libDirectory = Directory('lib');
+
+  await findNewestDartFileTimestamp(libDirectory).then((dateTime) {
+    final widgetNamesFile = File(_widgetNamesPath);
+    if (dateTime != null && widgetNamesFile.existsSync() && widgetNamesFile.lastModifiedSync().isAfter(dateTime)) {
+      resultCompleter.complete(true);
+    } else {
+      resultCompleter.complete(false);
+    }
+  });
+
+  return resultCompleter.future;
+}
+
+Future<DateTime?> findNewestDartFileTimestamp(Directory dir) async {
+  DateTime? newestTimestamp;
+
+  if (!await dir.exists()) {
+    return null;
+  }
+
+  await for (final FileSystemEntity entity in dir.list(recursive: true)) {
+    if (entity is File && entity.path.endsWith('.dart')) {
+      final DateTime lastModified = await entity.lastModified();
+
+      if (newestTimestamp == null || lastModified.isAfter(newestTimestamp)) {
+        newestTimestamp = lastModified;
+      }
+    }
+  }
+
+  return newestTimestamp;
+}

lib/src/widget/src/git_diffs.dart

@@ -0,0 +1,36 @@
+// ignore_for_file: avoid_print
+
+import 'dart:io';
+
+import 'package:approval_tests/src/widget/src/common.dart';
+
+void printGitDiffs(String testDescription, String differences) {
+  print(topBar);
+  print("Results of git diff during approvalTest('$testDescription'):");
+  print(differences.trim());
+  print(bottomBar);
+}
+
+/// return the diff of two files
+String gitDiffFiles(File path0, FileSystemEntity path1) {
+  final processResult = Process.runSync('git', ['diff', '--no-index', path0.path, path1.path]);
+
+  final stdoutString = processResult.stdout as String;
+  final stderrString = processResult.stderr as String;
+
+  final processString = stdoutString.isNotEmpty || stderrString.isNotEmpty ? stdoutString : '';
+
+  return _stripGitDiff(processString);
+}
+
+/// Format the git --diff if superfluous text
+String _stripGitDiff(String multiLineString) {
+  bool startsWithAny(String line, List<String> prefixes) => prefixes.any((prefix) => line.startsWith(prefix));
+
+  final List<String> lines = multiLineString.split('\n');
+  final List<String> filteredLines = lines.where((line) => !startsWithAny(line, ['diff', 'index', '@@'])).toList();
+
+  final String result = filteredLines.join('\n');
+
+  return result;
+}