Implement least upper bound.

tests/compiler/dart2js/warnings_checker.dart

Index: tests/compiler/dart2js/warnings_checker.dart
diff --git a/tests/compiler/dart2js/type_promotion_test.dart b/tests/compiler/dart2js/warnings_checker.dart
similarity index 72%
copy from tests/compiler/dart2js/type_promotion_test.dart
copy to tests/compiler/dart2js/warnings_checker.dart
index a25c2211a6f3a9f44d1ff5dbccb305bebefb422e..1105b38f521d77281a2ba269005696fe085d7668 100644
--- a/tests/compiler/dart2js/type_promotion_test.dart
+++ b/tests/compiler/dart2js/warnings_checker.dart
@@ -2,13 +2,13 @@
 // 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';
@@ -16,27 +16,11 @@ import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.
 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(
@@ -56,7 +40,7 @@ void main() {
          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')) {
@@ -92,5 +76,5 @@ void main() {
     });
   }).then((_) {
     Expect.isFalse(warningsMismatch);
-  });
+  }));
 }