feat(test): support --concurrency option (#416)

lib/src/commands/test/test.dart

@@ -55,6 +55,12 @@ class TestCommand extends Command<int> {
  defaultsTo: true,
  help: 'Whether to apply optimizations for test performance.',
  )
+ ..addOption(
+ 'concurrency',
+ abbr: 'j',
+ defaultsTo: '4',
+ help: 'The number of concurrent test suites run.',
+ )
  ..addOption(
  'exclude-coverage',
  help: 'A glob which will be used to exclude files that match from the '
@@ -112,6 +118,7 @@ This command should be run from the root of your Flutter project.''',
  return ExitCode.noInput.code;
  }
 
+ final concurrency = _argResults['concurrency'] as String;
  final recursive = _argResults['recursive'] as bool;
  final collectCoverage = _argResults['coverage'] as bool;
  final minCoverage = double.tryParse(
@@ -144,6 +151,7 @@ This command should be run from the root of your Flutter project.''',
  arguments: [
  if (excludeTags != null) ...['-x', excludeTags],
  if (updateGoldens) '--update-goldens',
+ ...['-j', concurrency],
  '--no-pub',
  ..._argResults.rest,
  ],

test/src/commands/test/test_test.dart

@@ -19,6 +19,8 @@ const expectedTestUsage = [
  '''-r, --recursive Run tests recursively for all nested packages.\n'''
  ''' --[no-]optimization Whether to apply optimizations for test performance.\n'''
  ' (defaults to on)\n'
+ '''-j, --concurrency The number of concurrent test suites run.\n'''
+ ' (defaults to "4")\n'
  ''' --exclude-coverage A glob which will be used to exclude files that match from the coverage.\n'''
  '''-x, --exclude-tags Run only tests that do not have the specified tags.\n'''
  ''' --min-coverage Whether to enforce a minimum coverage percentage.\n'''
@@ -54,7 +56,8 @@ class MockFlutterTestCommand extends Mock implements FlutterTestCommand {}
 void main() {
  group('test', () {
  final cwd = Directory.current;
- const defaultArguments = ['--no-pub'];
+ const concurrency = '4';
+ const defaultArguments = ['-j', concurrency, '--no-pub'];
 
  late Logger logger;
  late bool isFlutterInstalled;
@@ -88,6 +91,7 @@ void main() {
  stderr: any(named: 'stderr'),
  ),
  ).thenAnswer((_) async => [0]);
+ when<dynamic>(() => argResults['concurrency']).thenReturn(concurrency);
  when<dynamic>(() => argResults['recursive']).thenReturn(false);
  when<dynamic>(() => argResults['coverage']).thenReturn(false);
  when<dynamic>(() => argResults['update-goldens']).thenReturn(false);
@@ -189,6 +193,21 @@ void main() {
  ).called(1);
  });
 
+ test('completes normally --concurrency 1', () async {
+ when<dynamic>(() => argResults['concurrency']).thenReturn('1');
+ final result = await testCommand.run();
+ expect(result, equals(ExitCode.success.code));
+ verify(
+ () => flutterTest(
+ arguments: ['-j', '1', '--no-pub'],
+ optimizePerformance: true,
+ progress: logger.progress,
+ stdout: logger.write,
+ stderr: logger.err,
+ ),
+ ).called(1);
+ });
+
  test('completes normally --no-optimization', () async {
  when<dynamic>(() => argResults['optimization']).thenReturn(false);
  final result = await testCommand.run();