Change the URL-space exposed by the browser server.

test/runner/browser/loader_test.dart

Index: test/runner/browser/loader_test.dart
diff --git a/test/runner/browser/loader_test.dart b/test/runner/browser/loader_test.dart
index a3e93c5fe2c20cf6c957a3bdfd187a174a38bf39..322de04cd04951fa23aae36b8a98860f71eda259 100644
--- a/test/runner/browser/loader_test.dart
+++ b/test/runner/browser/loader_test.dart
@@ -33,9 +33,10 @@ void main() {
 
 void main() {
   setUp(() {
+    _sandbox = createTempDir();
     _loader = new Loader([TestPlatform.chrome],
+        root: _sandbox,
         packageRoot: p.join(packageDir, 'packages'));
-    _sandbox = createTempDir();
     /// TODO(nweiz): Use scheduled_test for this once it's compatible with this
     /// version of test.
     new File(p.join(_sandbox, 'a_test.dart')).writeAsStringSync(_tests);
@@ -88,7 +89,7 @@ void main() {
   });
 
   test("throws a nice error if the package root doesn't exist", () {
-    var loader = new Loader([TestPlatform.chrome]);
+    var loader = new Loader([TestPlatform.chrome], root: _sandbox);
     expect(
         loader.loadFile(p.join(_sandbox, 'a_test.dart')).first
             .whenComplete(loader.close),
@@ -98,6 +99,7 @@ void main() {
 
   test("loads a suite both in the browser and the VM", () {
     var loader = new Loader([TestPlatform.vm, TestPlatform.chrome],
+        root: _sandbox,
         packageRoot: p.join(packageDir, 'packages'));
     var path = p.join(_sandbox, 'a_test.dart');
     return loader.loadFile(path).toList().then((suites) {