[tests] Fix tests for changing type parameters

* Handle inconsistencies in the type of a notice in reload reports.
* Update expected error messages when the type parameters of a class
  change.
* Fail reload tests if rejection error was expected but the actual
  error is null.
* Cleanup unused imports in tests.
* Delete change_instance_format7 test because it was split into DDC
  and VM specific versions.

Change-Id: I3b4d6cb3126d7c1fad688c393677e053a005687f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/408883
Reviewed-by: Mark Zhou <markzipan@google.com>
Commit-Queue: Nicholas Shahan <nshahan@google.com>

pkg/dev_compiler/test/hot_reload_suite.dart

@@ -752,7 +752,7 @@ abstract class HotReloadSuiteRunner {
           return false;
         }
         final rejectionMessage = reloadReceipt.rejectionMessage;
-        if (rejectionMessage != null &&
+        if (rejectionMessage == null ||
             !rejectionMessage.contains(expectedError)) {
           _print(
               'Generation ${reloadReceipt.generation} was rejected but error '

pkg/reload_test/lib/src/_vm_reload_utils.dart

@@ -179,7 +179,8 @@ extension on ReloadReport {
     final notices = this.json?['notices'] as List?;
     if (notices != null) {
       for (final notice in notices) {
-        if (notice['type'] == 'ReasonForCancelling') {
+        if (notice['type'] == 'ReasonForCancelling' ||
+            notice['type'] == 'ReasonForCancellingReload') {
           return notice['message'] as String?;
         }
       }

tests/hot_reload/change_instance_format6/config.json

@@ -1,6 +1,5 @@
 {
   "expectedErrors": {
-    "1": "type parameters have changed"
+    "1": "Limitation: changing type parameters does not work with hot reload."
   }
 }
-

tests/hot_reload/change_instance_format6/main.0.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format6/main.1.reject.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format7/main.0.dart

@@ -1,23 +0,0 @@
-// Copyright (c) 2025, 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:expect/expect.dart';
-import 'package:reload_test/reload_test_utils.dart';
-
-// Adapted from:
-// https://github.com/dart-lang/sdk/blob/1a486499bf73ee5b007abbe522b94869a1f36d02/runtime/vm/isolate_reload_test.cc#L4051
-
-// Tests reload succeeds when type parameters are changed for allocated class.
-// Change: Foo<A,B> {a, b} -> Foo<A> {a}
-// Validate: return value from main is correct.
-// Please note: This test works because no instances are created from Foo.
-
-class Foo<A, B> {
-  var a;
-  var b;
-}
-
-Future<void> main() async {
-  await hotReload();
-}

tests/hot_reload/change_instance_format7/main.1.dart

@@ -1,36 +0,0 @@
-// Copyright (c) 2025, 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:expect/expect.dart';
-import 'package:reload_test/reload_test_utils.dart';
-
-// Adapted from:
-// https://github.com/dart-lang/sdk/blob/1a486499bf73ee5b007abbe522b94869a1f36d02/runtime/vm/isolate_reload_test.cc#L4051
-
-// Tests reload succeeds when type parameters are changed for allocated class.
-// Change: Foo<A,B> {a, b} -> Foo<A> {a}
-// Validate: return value from main is correct.
-// Please note: This test works because no instances are created from Foo.
-
-class Foo<A> {
-  var a;
-}
-
-Future<void> main() async {
-  await hotReload();
-}
-
-/** DIFF **/
-/*
- // Validate: return value from main is correct.
- // Please note: This test works because no instances are created from Foo.
- 
--class Foo<A, B> {
-+class Foo<A> {
-   var a;
--  var b;
- }
- 
- Future<void> main() async {
-*/

tests/hot_reload/change_instance_format7_ddc/config.json

@@ -1,6 +1,8 @@
 {
-  "exclude": ["vm"],
+  "exclude": [
+    "vm"
+  ],
   "expectedErrors": {
-    "1": "type parameters have changed"
+    "1": "Limitation: changing type parameters does not work with hot reload."
   }
 }

tests/hot_reload/change_instance_format7_ddc/main.0.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format7_ddc/main.1.reject.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format7_vm/main.0.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format7_vm/main.1.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format9/config.json

@@ -1,6 +1,5 @@
 {
   "expectedErrors": {
-    "1": "type parameters have changed"
+    "1": "Limitation: changing type parameters does not work with hot reload."
   }
 }
-

tests/hot_reload/change_instance_format9/main.0.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from:

tests/hot_reload/change_instance_format9/main.1.reject.dart

@@ -2,7 +2,6 @@
 // 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:expect/expect.dart';
 import 'package:reload_test/reload_test_utils.dart';
 
 // Adapted from: