Add RunnerSuite.{on,is}Debugging properties.

lib/src/runner/load_suite.dart

Index: lib/src/runner/load_suite.dart
diff --git a/lib/src/runner/load_suite.dart b/lib/src/runner/load_suite.dart
index cb84a0b5121ee73be5211249f04013de2bc69c7d..74f25f7ad971ca0ead99ae916f5d7b363e2b19c6 100644
--- a/lib/src/runner/load_suite.dart
+++ b/lib/src/runner/load_suite.dart
@@ -12,6 +12,7 @@ import '../../test.dart';
 import '../backend/group.dart';
 import '../backend/invoker.dart';
 import '../backend/metadata.dart';
+import '../backend/suite.dart';
 import '../backend/test.dart';
 import '../backend/test_platform.dart';
 import '../utils.dart';
@@ -33,7 +34,11 @@ import 'vm/environment.dart';
 /// a normal test body, this logic isn't run until [LiveTest.run] is called. The
 /// suite itself is returned by [suite] once it's avaialble, but any errors or
 /// prints will be emitted through the running [LiveTest].
-class LoadSuite extends RunnerSuite {
+class LoadSuite extends Suite implements RunnerSuite {
+  final environment = const VMEnvironment();
+  final isDebugging = false;
+  final onDebugging = new StreamController<bool>().stream;
+
   /// A future that completes to the loaded suite once the suite's test has been
   /// run and completed successfully.
   ///
@@ -77,7 +82,8 @@ class LoadSuite extends RunnerSuite {
             return;
           }
 
-          completer.complete(new Pair(suite, Zone.current));
+          completer.complete(
+              suite == null ? null : new Pair(suite, Zone.current));
           invoker.removeOutstandingCallback();
         } catch (error, stackTrace) {
           registerException(error, stackTrace);
@@ -115,7 +121,7 @@ class LoadSuite extends RunnerSuite {
 
   LoadSuite._(String name, void body(), this._suiteAndZone,
           {TestPlatform platform})
-      : super(const VMEnvironment(), new Group.root([
+      : super(new Group.root([
         new LocalTest(name,
             new Metadata(timeout: new Timeout(new Duration(minutes: 5))),
             body)
@@ -123,7 +129,7 @@ class LoadSuite extends RunnerSuite {
 
   /// A constructor used by [changeSuite].
   LoadSuite._changeSuite(LoadSuite old, this._suiteAndZone)
-      : super(const VMEnvironment(), old.group, platform: old.platform);
+      : super(old.group, platform: old.platform);
 
   /// Creates a new [LoadSuite] that's identical to this one, but that
   /// transforms [suite] once it's loaded.
@@ -136,7 +142,8 @@ class LoadSuite extends RunnerSuite {
       if (pair == null) return null;
 
       var zone = pair.last;
-      return new Pair(zone.runUnaryGuarded(change, pair.first), zone);
+      var newSuite = zone.runUnaryGuarded(change, pair.first);
+      return newSuite == null ? null : new Pair(newSuite, zone);
     }));
   }
 
@@ -155,4 +162,6 @@ class LoadSuite extends RunnerSuite {
     await new Future.error(error.error, error.stackTrace);
     throw 'unreachable';
   }
+
+  Future close() async {}
 }