Make pubspec.lock keep relative path if it is originally specified as relative in pubspec.yaml (iss…

sdk/lib/_internal/pub/test/get/path/relative_path_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 d.file.
 
+import 'package:path/path.dart' as path;
+import 'package:scheduled_test/scheduled_test.dart';
+import 'package:unittest/unittest.dart';
+
+import '../../../lib/src/lock_file.dart';
+import '../../../lib/src/source_registry.dart';
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration("can use relative path", () {
     d.dir("foo", [
       d.libDir("foo"),
       d.libPubspec("foo", "0.0.1")
     ]).create();
@@ skipping 37 matching lines @@
 
     d.dir(packagesPath, [
       d.dir("foo", [
         d.file("foo.dart", 'main() => "foo";')
       ]),
       d.dir("bar", [
         d.file("bar.dart", 'main() => "bar";')
       ])
     ]).validate();
   });
+  
+  integration("relative path preserved in the lockfile", () {
+    d.dir("foo", [
+      d.libDir("foo"),
+      d.libPubspec("foo", "0.0.1")
+    ]).create();
+
+    d.dir(appPath, [
+      d.appPubspec({
+        "foo": {"path": "../foo"}
+      })
+    ]).create();
+
+    pubGet();
+
+    schedule(() {
+      var lockfilePath = path.join(sandboxDir, appPath, "pubspec.lock");
+      var lockfile = new LockFile.load(lockfilePath, new SourceRegistry());
+      var description = lockfile.packages["foo"].description;
+
+      expect(path.isRelative(description["path"]), isTrue);
+    });
+  });
 }