migrate malformed pubspec integration test

test/all.dart

@@ -11,6 +11,7 @@ import 'engine_test.dart' as engine_test;
 import 'formatter_test.dart' as formatter_test;
 import 'integration_test.dart' as integration_test;
 import 'mocks.dart';
+import 'pubspec_test.dart' as pubspec_test;
 import 'rule_test.dart' as rule_test;
 import 'rules/all.dart' as reflective_rule_tests;
 import 'unmocked_sdk_rule_test.dart' as unmocked_sdk_rule_test;
@@ -37,6 +38,7 @@ void main() {
   engine_test.main();
   formatter_test.main();
   integration_test.main();
+  pubspec_test.main();
   rule_test.main();
   reflective_rule_tests.main();
   unmocked_sdk_rule_test.main();

test/integration_test.dart

@@ -77,24 +77,6 @@ void coreTests() {
       });
     });
 
-    group('pubspec', () {
-      var currentOut = outSink;
-      var collectingOut = CollectingSink();
-      setUp(() => outSink = collectingOut);
-      tearDown(() {
-        collectingOut.buffer.clear();
-        outSink = currentOut;
-      });
-      test('bad pubspec', () async {
-        await cli.run([
-          '$integrationTestDir/p3',
-          '$integrationTestDir/p3/_pubpspec.yaml'
-        ]);
-        expect(collectingOut.trim(),
-            startsWith('1 file analyzed, 0 issues found, in'));
-      });
-    });
-
     group('canonicalization', () {
       var currentOut = outSink;
       var collectingOut = CollectingSink();

test/pubspec_test.dart

@@ -0,0 +1,29 @@
+// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import 'rule_test_support.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(BadPubspecTest);
+  });
+}
+
+@reflectiveTest
+class BadPubspecTest extends LintRuleTest {
+  @override
+  String get lintRule => 'sort_pub_dependencies';
+
+  // ignore: non_constant_identifier_names
+  test_malformedPubspec() async {
+    await assertNoPubspecDiagnostics(r'''
+not: a
+  valid
+ pub
+  spec:
+''');
+  }
+}