Change the way Patterns work in scheduled_test/descriptor.

pkg/scheduled_test/lib/src/descriptor/nothing.dart

Index: pkg/scheduled_test/lib/src/descriptor/nothing.dart
diff --git a/pkg/scheduled_test/lib/src/descriptor/nothing.dart b/pkg/scheduled_test/lib/src/descriptor/nothing.dart
index 9a1f1b4c6fe48c1a69b8a5889989f088ddcd164b..9b9254350d2048573171c9905d487043ce5d20a2 100644
--- a/pkg/scheduled_test/lib/src/descriptor/nothing.dart
+++ b/pkg/scheduled_test/lib/src/descriptor/nothing.dart
@@ -12,43 +12,30 @@ import '../../../../../pkg/pathos/lib/path.dart' as path;
 import '../../descriptor.dart' as descriptor;
 import '../../scheduled_test.dart';
 import '../utils.dart';
-import 'utils.dart';
 
 /// A descriptor that validates that no file exists with the given name.
 /// Creating this descriptor is a no-op and loading from it is invalid.
 class Nothing extends descriptor.Entry {
-  Nothing(Pattern name)
+  Nothing(String name)
       : super(name);
 
   Future create([String parent]) => new Future.immediate(null);
 
-  Future validate([String parent]) => schedule(() {
+  Future validate([String parent]) => schedule(() => validateNow(parent),
+      "validating '$name' doesn't exist");
+
+  Future validateNow([String parent]) => new Future.of(() {
     if (parent == null) parent = descriptor.defaultRoot;
-    if (name is String) {
-      var fullPath = path.join(parent, name);
-      if (new File(fullPath).existsSync()) {
-        throw "Expected nothing to exist at '$fullPath', but found a file.";
-      } else if (new Directory(fullPath).existsSync()) {
-        throw "Expected nothing to exist at '$fullPath', but found a "
-            "directory.";
-      } else {
-        return;
-      }
+    var fullPath = path.join(parent, name);
+    if (new File(fullPath).existsSync()) {
+      throw "Expected nothing to exist at '$fullPath', but found a file.";
+    } else if (new Directory(fullPath).existsSync()) {
+      throw "Expected nothing to exist at '$fullPath', but found a "
+          "directory.";
+    } else {
+      return;
     }
-
-    return new Directory(parent).list().toList().then((entries) {
-      var matchingEntries = entries
-          .map((entry) => entry is File ? entry.fullPathSync() : entry.path)
-          .where((entry) => path.basename(entry).contains(name))
-          .toList();
-      matchingEntries.sort();
-
-      if (matchingEntries.length == 0) return;
-      throw "Expected nothing to exist in '$parent' matching $nameDescription, "
-              "but found:\n"
-          "${matchingEntries.map((entry) => '* $entry').join('\n')}";
-    });
-  }, "validating $nameDescription doesn't exist");
+  });
 
   Stream<List<int>> load(String pathToLoad) => errorStream("Nothing "
       "descriptors don't support load().");
@@ -56,5 +43,5 @@ class Nothing extends descriptor.Entry {
   Stream<List<int>> read() => errorStream("Nothing descriptors don't support "
       "read().");
 
-  String describe() => "nothing at $nameDescription";
+  String describe() => "nothing at '$name'";
 }