Implement least upper bound.

tests/compiler/dart2js/warnings_checker.dart

 // Copyright (c) 2013, 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.
 
-// Test that dart2js produces the expected static type warnings for type
-// promotion langauge tests. This ensures that the analyzer and dart2js agrees
-// on these tests.
+// Test that dart2js produces the expected static type warnings to ensures that
+// the analyzer and dart2js agrees on the tests.
 
 import 'dart:async';
 import 'dart:io';
 import 'package:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
 import 'memory_compiler.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/filenames.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/util/uri_extras.dart';
 import 'dart:convert';
 
-/// Map from test files to a map of their expected status. If the status map is
-/// `null` no warnings must be missing or unexpected, otherwise the status map
-/// can contain a list of line numbers for keys 'missing' and 'unexpected' for
-/// the warnings of each category.
-const Map<String, dynamic> TESTS = const {
-    'language/type_promotion_assign_test.dart': null,
-    'language/type_promotion_closure_test.dart': null,
-    'language/type_promotion_functions_test.dart':
-        const {'missing': const [62, 63, 64]}, // Issue 14933.
-    'language/type_promotion_local_test.dart': null,
-    'language/type_promotion_logical_and_test.dart': null,
-    'language/type_promotion_more_specific_test.dart': null,
-    'language/type_promotion_multiple_test.dart': null,
-    'language/type_promotion_parameter_test.dart': null,
-};
-
-void main() {
+void checkWarnings(Map<String, dynamic> tests) {
   bool isWindows = Platform.isWindows;
   Uri script = currentDirectory.resolveUri(Platform.script);
   bool warningsMismatch = false;
-  Future.forEach(TESTS.keys, (String test) {
+  asyncTest(() => Future.forEach(tests.keys, (String test) {
     Uri uri = script.resolve('../../$test');
     String source = UTF8.decode(readAll(uriPathToNative(uri.path)));
     SourceFile file = new StringSourceFile(
         relativize(currentDirectory, uri, isWindows), source);
     Map<int,String> expectedWarnings = {};
     int lineNo = 0;
     for (String line in source.split('\n')) {
       if (line.contains('///') && line.contains('static type warning')) {
         expectedWarnings[lineNo] = line;
       }
       lineNo++;
     }
     Set<int> unseenWarnings = new Set<int>.from(expectedWarnings.keys);
     DiagnosticCollector collector = new DiagnosticCollector();
     var compiler = compilerFor(const {},
          diagnosticHandler: collector,
          options: ['--analyze-only'],
          showDiagnostics: false);
     return compiler.run(uri).then((_) {
-      Map<String, List<int>> statusMap = TESTS[test];
+      Map<String, List<int>> statusMap = tests[test];
       // Line numbers with known unexpected warnings.
       List<int> unexpectedStatus = [];
       if (statusMap != null && statusMap.containsKey('unexpected')) {
         unexpectedStatus = statusMap['unexpected'];
       }
       // Line numbers with known missing warnings.
       List<int> missingStatus = [];
       if (statusMap != null && statusMap.containsKey('missing')) {
         missingStatus = statusMap['missing'];
       }
@@ skipping 15 matching lines @@
             warningsMismatch = true;
             String line = expectedWarnings[lineNo];
             print('$uri [${lineNo+1}]: Missing static type warning.');
             print(line);
           }
         }
       }
     });
   }).then((_) {
     Expect.isFalse(warningsMismatch);
-  });
+  }));
 }