Use "package:" imports for pub.

test/version_solver_test.dart

Index: test/version_solver_test.dart
diff --git a/test/version_solver_test.dart b/test/version_solver_test.dart
index d025ed7fd7e5250eb61beaa205321f1662d2cb93..ee3176e3423fcdc74c0b7a817f416cd9709d34d5 100644
--- a/test/version_solver_test.dart
+++ b/test/version_solver_test.dart
@@ -6,18 +6,18 @@ library pub_upgrade_test;
 
 import 'dart:async';
 
+import 'package:pub/src/lock_file.dart';
+import 'package:pub/src/log.dart' as log;
+import 'package:pub/src/package.dart';
+import 'package:pub/src/pubspec.dart';
+import 'package:pub/src/sdk.dart' as sdk;
+import 'package:pub/src/solver/version_solver.dart';
+import 'package:pub/src/source/cached.dart';
+import 'package:pub/src/system_cache.dart';
+import 'package:pub/src/utils.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:unittest/unittest.dart';
 
-import '../lib/src/lock_file.dart';
-import '../lib/src/log.dart' as log;
-import '../lib/src/package.dart';
-import '../lib/src/pubspec.dart';
-import '../lib/src/sdk.dart' as sdk;
-import '../lib/src/source/cached.dart';
-import '../lib/src/system_cache.dart';
-import '../lib/src/utils.dart';
-import '../lib/src/solver/version_solver.dart';
 import 'test_pub.dart';
 
 MockSource source1;