Support for @JS() validation (#26225).

pkg/analyzer/test/generated/hint_code_test.dart

Index: pkg/analyzer/test/generated/hint_code_test.dart
diff --git a/pkg/analyzer/test/generated/hint_code_test.dart b/pkg/analyzer/test/generated/hint_code_test.dart
index fa3da216fadc4f776d7becfc8124e281c4ad2bae..b79590e25079927fe006ec900d01bd310a98e901 100644
--- a/pkg/analyzer/test/generated/hint_code_test.dart
+++ b/pkg/analyzer/test/generated/hint_code_test.dart
@@ -132,6 +132,12 @@ class _Required {
   final String reason;
   const _Required([this.reason]));
 }
+''',
+      'package:js/js.dart': r'''
+library js;
+class JS {
+  const JS([String js]) { }
+}
 '''
     });
   }
@@ -1241,6 +1247,35 @@ main() {
     verify([source]);
   }
 
+  void test_js_lib_OK() {
+    Source source = addSource(r'''
+@JS()
+library foo;
+
+import 'package:js/js.dart';
+
+@JS()
+class A { }
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_missing_js_lib() {

[Brian Wilkerson, 2016/04/08 19:15:31]

Maybe also test it on a class member (if that's allowed).

[pquitslund, 2016/04/08 20:29:42]

Done.

+    Source source = addSource(r'''
+library foo;
+
+import 'package:js/js.dart';
+
+@JS()
+class A { }
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.MISSING_JS_LIB_ANNOTATION]);
+    verify([source]);
+  }
+

[terry, 2016/04/08 19:38:57]

May want to test top-level function use of @JS

@JS('acxZIndex')
external int set _currentZIndex(int value);

[pquitslund, 2016/04/08 20:29:42]

Done.

   void test_missingReturn_async() {
     Source source = addSource('''
 import 'dart:async';