Move unnecessary_constructor_name tests (#4501)

test/rules/all.dart

@@ -133,6 +133,7 @@ import 'unnecessary_brace_in_string_interps_test.dart'
     as unnecessary_brace_in_string_interps;
 import 'unnecessary_breaks_test.dart' as unnecessary_breaks;
 import 'unnecessary_const_test.dart' as unnecessary_const;
+import 'unnecessary_constructor_name_test.dart' as unnecessary_constructor_name;
 import 'unnecessary_final_test.dart' as unnecessary_final;
 import 'unnecessary_lambdas_test.dart' as unnecessary_lambdas;
 import 'unnecessary_library_directive_test.dart'
@@ -261,6 +262,7 @@ void main() {
   unnecessary_brace_in_string_interps.main();
   unnecessary_breaks.main();
   unnecessary_const.main();
+  unnecessary_constructor_name.main();
   unnecessary_final.main();
   unnecessary_lambdas.main();
   unnecessary_library_directive.main();

test/rules/unnecessary_constructor_name_test.dart

@@ -0,0 +1,70 @@
+// 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(UnnecessaryConstructorNameTest);
+  });
+}
+
+@reflectiveTest
+class UnnecessaryConstructorNameTest extends LintRuleTest {
+  @override
+  String get lintRule => 'unnecessary_constructor_name';
+
+  test_constructorDeclaration_named() async {
+    await assertNoDiagnostics(r'''
+class A {
+  A.ok();
+}
+''');
+  }
+
+  test_constructorDeclaration_new() async {
+    await assertDiagnostics(r'''
+class A {
+  A.new();
+}
+''', [
+      lint(14, 3),
+    ]);
+  }
+
+  test_constructorTearoff_new() async {
+    await assertNoDiagnostics(r'''
+class A {
+}
+var makeA = A.new;
+''');
+  }
+
+  test_instanceCreation_named() async {
+    await assertNoDiagnostics(r'''
+class A {
+  A.ok();
+}
+var aaa = A.ok();
+''');
+  }
+
+  test_instanceCreation_new() async {
+    await assertDiagnostics(r'''
+class A {}
+var a = A.new();
+''', [
+      lint(21, 3),
+    ]);
+  }
+
+  test_instanceCreation_unnamed() async {
+    await assertNoDiagnostics(r'''
+class A {}
+var aa = A();
+''');
+  }
+}