[hooks] testBuildHook: Emit output validation errors (#2735)

Author: simolus3

pkgs/hooks/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.20.6-wip
+
+- Fix `testBuildHook` to emit output validation errors if there are any.
+
 ## 0.20.5
 
 - Document `input.packageRoot` in more places.

pkgs/hooks/lib/src/test.dart

@@ -106,7 +106,7 @@ Future<void> testBuildHook({
     ];
     if (outputErrors.isNotEmpty) {
       throw ValidationFailure(
-        'Encountered build output validation issues: $inputErrors',
+        'Encountered build output validation issues: $outputErrors',
       );
     }
 

pkgs/hooks/pubspec.yaml

@@ -3,7 +3,7 @@ description: >-
   A library that contains a Dart API for the JSON-based protocol for
   `hook/build.dart` and `hook/link.dart`.
 
-version: 0.20.5
+version: 0.20.6-wip
 
 repository: https://github.com/dart-lang/native/tree/main/pkgs/hooks
 

pkgs/hooks/test/test_test.dart

@@ -0,0 +1,55 @@
+// 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:code_assets/code_assets.dart';
+import 'package:hooks/hooks.dart';
+import 'package:hooks/src/validation.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('throws on output error', () async {
+    final testResult = testBuildHook(
+      mainMethod: (args) async {
+        await build(args, (input, output) async {
+          output.assets.code.add(
+            CodeAsset(
+              package: 'foreign_package',
+              name: 'foo.dart',
+              linkMode: DynamicLoadingSystem(Uri.parse('libbrokenstuff.so')),
+            ),
+          );
+        });
+      },
+      extensions: [
+        CodeAssetExtension(
+          targetArchitecture: Architecture.current,
+          targetOS: OS.current,
+          linkModePreference: LinkModePreference.preferDynamic,
+          macOS: OS.current == OS.macOS
+              ? MacOSCodeConfig(targetVersion: 13)
+              : null,
+        ),
+      ],
+      check: expectAsync2((_, _) {}, count: 0),
+    );
+
+    expect(
+      testResult,
+      throwsA(
+        isA<ValidationFailure>().having(
+          (e) => e.message,
+          'message',
+          contains(
+            'output validation issues: [Code asset '
+            '"package:foreign_package/foo.dart" does not start with '
+            // We don't know the expected prefix here because this test can be
+            // run from the hooks package or the workspace. We just want to
+            // assert some message related to outputs gets thrown.
+            '"package:',
+          ),
+        ),
+      ),
+    );
+  });
+}