Clean up version solver tests a bit.

sdk/lib/_internal/pub/lib/src/package.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.
 
 library pub.package;
 
 import 'package:path/path.dart' as path;
 
 import 'io.dart';
 import 'pubspec.dart';
@@ skipping 93 matching lines @@
     return "$name from $source";
   }
 
   /// Returns a [PackageRef] with this one's [name], [source], and
   /// [description].
   PackageRef toRef() => new PackageRef(name, source, description);
 
   /// Returns a [PackageId] for this package with the given concrete version.
   PackageId atVersion(Version version) =>
     new PackageId(name, source, version, description);
+
+  /// Returns a [PackageDep] for this package with the given version constraint.
+  PackageDep withConstraint(VersionConstraint constraint) =>
+    new PackageDep(name, source, constraint, description);
 }
 
 /// A reference to a [Package], but not any particular version(s) of it.
 class PackageRef extends _PackageName {
   PackageRef(String name, String source, description)
       : super(name, source, description);
 
   int get hashCode => name.hashCode ^ source.hashCode;
 
   bool operator ==(other) {
@@ skipping 58 matching lines @@
 
   bool operator ==(other) {
     // TODO(rnystrom): We're assuming here that we don't need to delve into the
     // description.
     return other is PackageDep &&
            other.name == name &&
            other.source == source &&
            other.constraint == constraint;
   }
 }