fix: allow spaced golden file names

.github/workflows/e2e.yaml

@@ -32,6 +32,7 @@ jobs:
           # E2E tests for the test command
           - test/commands/test/async_main/async_main_test.dart
           - test/commands/test/no_project/no_project_test.dart
+          - test/commands/test/spaced_golden_file_name/spaced_golden_file_name_test.dart
 
           # E2E tests for the create command
           - test/commands/create/flutter_app/core_test.dart

e2e/test/commands/test/spaced_golden_file_name/fixture/pubspec.yaml

@@ -0,0 +1,14 @@
+name: spaced_golden_file_name
+description: Fixture for testing golden files with spaced file names.
+publish_to: none
+
+environment:
+  sdk: ">=2.18.0 <3.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

e2e/test/commands/test/spaced_golden_file_name/fixture/test/spaced_golden_file_name_test.dart

@@ -0,0 +1,14 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('renders SizedBox', (tester) async {
+    final widget = SizedBox.shrink();
+    await tester.pumpWidget(widget);
+
+    await expectLater(
+      find.byWidget(widget),
+      matchesGoldenFile('sized box.png'),
+    );
+  });
+}

e2e/test/commands/test/spaced_golden_file_name/spaced_golden_file_name_test.dart

@@ -0,0 +1,39 @@
+import 'package:mason/mason.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:test/test.dart';
+import 'package:universal_io/io.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  test(
+    'allows golden files with spaces in the name',
+    timeout: const Timeout(Duration(minutes: 2)),
+    withRunner((commandRunner, logger, updater, logs) async {
+      final tempDirectory = Directory.systemTemp.createTempSync('async_main');
+      addTearDown(() => tempDirectory.deleteSync(recursive: true));
+
+      await copyDirectory(
+        Directory('test/commands/test/spaced_golden_file_name/fixture'),
+        tempDirectory,
+      );
+
+      await expectSuccessfulProcessResult(
+        'flutter',
+        ['pub', 'get'],
+        workingDirectory: tempDirectory.path,
+      );
+      await expectSuccessfulProcessResult(
+        'flutter',
+        ['test', '--update-goldens'],
+        workingDirectory: tempDirectory.path,
+      );
+
+      Directory.current = tempDirectory;
+      final result = await commandRunner.run(['test']);
+
+      verifyNever(() => logger.err(any()));
+      expect(result, equals(ExitCode.success.code));
+    }),
+  );
+}