Add more tests for .packages

tests/standalone/package/scenarios/packages_file_strange_formatting/empty_package_dir_test.dart

Index: tests/standalone/package/scenarios/packages_file_strange_formatting/empty_package_dir_test.dart
diff --git a/tests/standalone/package/scenarios/packages_file_strange_formatting/empty_package_dir_test.dart b/tests/standalone/package/scenarios/packages_file_strange_formatting/empty_package_dir_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5c7eb399bb77baa82a1c72d1c2a38c4d9d37376a
--- /dev/null
+++ b/tests/standalone/package/scenarios/packages_file_strange_formatting/empty_package_dir_test.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2015, 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.
+
+// PackageRoot=none
+// Packages=empty_package_dir.packages
+
+// In this test, we give a packages file that associates the package 'foo' with
+// the empty string. This causes both the VM and dart2js to resolve
+// 'package:foo' imports relative to the root directory. So the import statement
+// `import 'package:foo/foo.dart'` is equivalent to `import '/foo.dart'`.
+library empty_package_dir_test;
+
+import 'package:foo/foo.dart';
+
+main() {
+}