Add support for Flutter SDK constraints.

test/lock_file_test.dart

 // Copyright (c) 2012, 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:pub/src/lock_file.dart';
 import 'package:pub/src/package.dart';
 import 'package:pub/src/source.dart';
 import 'package:pub/src/source_registry.dart';
 import 'package:pub/src/system_cache.dart';
 import 'package:pub_semver/pub_semver.dart';
@@ skipping 84 matching lines @@
         expect(foo.source, equals(sources['bad']));
       });
 
       test("allows an empty dependency map", () {
         var lockFile = new LockFile.parse('''
 packages:
 ''', sources);
         expect(lockFile.packages, isEmpty);
       });
 
+      test("allows an old-style SDK constraint", () {
+        var lockFile = new LockFile.parse('sdk: ">=1.2.3 <4.0.0"', sources);
+        expect(lockFile.dartSdkConstraint,
+            equals(new VersionConstraint.parse('>=1.2.3 <4.0.0')));
+        expect(lockFile.flutterSdkConstraint, isNull);
+      });
+
+      test("allows new-style SDK constraints", () {
+        var lockFile = new LockFile.parse('''
+sdks:
+  dart: ">=1.2.3 <4.0.0"
+  flutter: ^0.1.2
+''', sources);
+        expect(lockFile.dartSdkConstraint,
+            equals(new VersionConstraint.parse('>=1.2.3 <4.0.0')));
+        expect(lockFile.flutterSdkConstraint,
+            equals(new VersionConstraint.parse('^0.1.2')));
+      });
+
       test("throws if the top level is not a map", () {
         expect(() {
           new LockFile.parse('''
 not a map
 ''', sources);
         }, throwsFormatException);
       });
 
       test("throws if the contents of 'packages' is not a map", () {
         expect(() {
@@ skipping 53 matching lines @@
           new LockFile.parse('''
 packages:
   foo:
     version: 1.2.3
     source: mock
     description: foo desc is bad
 ''', sources);
         }, throwsFormatException);
       });
 
+      test("throws if the old-style SDK constraint isn't a string", () {
+        expect(() => new LockFile.parse('sdk: 1.0', sources),
+            throwsFormatException);
+      });
+
+      test("throws if the old-style SDK constraint is invalid", () {
+        expect(() => new LockFile.parse('sdk: oops', sources),
+            throwsFormatException);
+      });
+
+      test("throws if the sdks field isn't a map", () {
+        expect(() => new LockFile.parse('sdks: oops', sources),
+            throwsFormatException);
+      });
+
+      test("throws if an sdk constraint isn't a string", () {
+        expect(() => new LockFile.parse('sdks: {dart: 1.0}', sources),
+            throwsFormatException);
+        expect(() {
+          new LockFile.parse('sdks: {dart: 1.0.0, flutter: 1.0}', sources);
+        }, throwsFormatException);
+      });
+
+      test("throws if an sdk constraint is invalid", () {
+        expect(() => new LockFile.parse('sdks: {dart: oops}', sources),
+            throwsFormatException);
+        expect(() {
+          new LockFile.parse('sdks: {dart: 1.0.0, flutter: oops}', sources);
+        }, throwsFormatException);
+      });
+
       test("ignores extra stuff in file", () {
         new LockFile.parse('''
 extra:
   some: stuff
 packages:
   foo:
     bonus: not used
     version: 1.2.3
     source: mock
     description: foo desc
 ''', sources);
       });
     });
 
     test('serialize() dumps the lockfile to YAML', () {
       var lockfile = new LockFile([
         new PackageId(
           'foo', mockSource, new Version.parse('1.2.3'), 'foo desc'),
         new PackageId('bar', mockSource, new Version.parse('3.2.1'), 'bar desc')
       ]);
 
       expect(loadYaml(lockfile.serialize(null)), equals({
-        'sdk': 'any',
+        'sdks': {'dart': 'any'},
         'packages': {
           'foo': {
             'version': '1.2.3',
             'source': 'mock',
             'description': 'foo desc'
           },
           'bar': {
             'version': '3.2.1',
             'source': 'mock',
             'description': 'bar desc'
           }
         }
       }));
     });
   });
 }