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

pkg/analyzer/test/generated/hint_code_test.dart

 // Copyright (c) 2016, 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.
 
 library analyzer.test.generated.hint_code_test;
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 114 matching lines @@
 class _Override {
   const _Override();
 }
 class _Protected {
   const _Protected();
 }
 class _Required {
   final String reason;
   const _Required([this.reason]));
 }
+''',
+      'package:js/js.dart': r'''
+library js;
+class JS {
+  const JS([String js]) { }
+}
 '''
     });
   }
 
   void test_argumentTypeNotAssignable_functionType() {
     Source source = addSource(r'''
 m() {
   var a = new A();
   a.n(() => 0);
 }
@@ skipping 1089 matching lines @@
   void test_isNotDouble() {
     AnalysisOptionsImpl options = new AnalysisOptionsImpl();
     options.dart2jsHint = true;
     resetWithOptions(options);
     Source source = addSource("var v = 1 is! double;");
     computeLibrarySourceErrors(source);
     assertErrors(source, [HintCode.IS_NOT_DOUBLE]);
     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_on_class_decl() {
+    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]);
+  }
+
+  void test_missing_js_lib_on_function() {
+    Source source = addSource(r'''
+library foo;
+
+import 'package:js/js.dart';
+
+@JS('acxZIndex')
+set _currentZIndex(int value) { }
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.MISSING_JS_LIB_ANNOTATION]);
+    verify([source]);
+  }
+
+  void test_missing_js_lib_on_member() {
+    Source source = addSource(r'''
+library foo;
+
+import 'package:js/js.dart';
+
+class A {
+  @JS()
+  void a() { }
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.MISSING_JS_LIB_ANNOTATION]);
+    verify([source]);
+  }
+
   void test_missingReturn_async() {
     Source source = addSource('''
 import 'dart:async';
 Future<int> f() async {}
 ''');
     computeLibrarySourceErrors(source);
     assertErrors(source, [HintCode.MISSING_RETURN]);
     verify([source]);
   }
 
@@ skipping 1921 matching lines @@
   n() {
     var a = m(), b = m();
   }
 }''');
     computeLibrarySourceErrors(source);
     assertErrors(
         source, [HintCode.USE_OF_VOID_RESULT, HintCode.USE_OF_VOID_RESULT]);
     verify([source]);
   }
 }