feat(test): support --tags option (#421)

Author: agacemi

lib/src/commands/test/test.dart

@@ -50,6 +50,11 @@ class TestCommand extends Command<int> {
         help: 'Run tests recursively for all nested packages.',
         negatable: false,
       )
+      ..addOption(
+        'tags',
+        abbr: 't',
+        help: 'Run only tests associated with the specified tags.',
+      )
       ..addFlag(
         'optimization',
         defaultsTo: true,
@@ -125,6 +130,7 @@ This command should be run from the root of your Flutter project.''',
       _argResults['min-coverage'] as String? ?? '',
     );
     final excludeTags = _argResults['exclude-tags'] as String?;
+    final tags = _argResults['tags'] as String?;
     final isFlutterInstalled = await _flutterInstalled();
     final excludeFromCoverage = _argResults['exclude-coverage'] as String?;
     final randomOrderingSeed =
@@ -150,6 +156,7 @@ This command should be run from the root of your Flutter project.''',
           randomSeed: randomSeed,
           arguments: [
             if (excludeTags != null) ...['-x', excludeTags],
+            if (tags != null) ...['-t', tags],
             if (updateGoldens) '--update-goldens',
             ...['-j', concurrency],
             '--no-pub',

test/src/commands/test/test_test.dart

@@ -17,6 +17,7 @@ const expectedTestUsage = [
       '-h, --help                            Print this usage information.\n'
       '''    --coverage                        Whether to collect coverage information.\n'''
       '''-r, --recursive                       Run tests recursively for all nested packages.\n'''
+      '''-t, --tags                            Run only tests associated with the specified tags.\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'''
@@ -290,6 +291,21 @@ void main() {
       ).called(1);
     });
 
+    test('completes normally -t test-tag', () async {
+      when<dynamic>(() => argResults['tags']).thenReturn('test-tag');
+      final result = await testCommand.run();
+      expect(result, equals(ExitCode.success.code));
+      verify(
+        () => flutterTest(
+          optimizePerformance: true,
+          arguments: ['-t', 'test-tag', ...defaultArguments],
+          progress: logger.progress,
+          stdout: logger.write,
+          stderr: logger.err,
+        ),
+      ).called(1);
+    });
+
     test('completes normally -x test-tag', () async {
       when<dynamic>(() => argResults['exclude-tags']).thenReturn('test-tag');
       final result = await testCommand.run();