diff --git a/packages/livedata/livedata_tests.js b/packages/livedata/livedata_tests.js
index 39c29b741c..28b52a8f16 100644
--- a/packages/livedata/livedata_tests.js
+++ b/packages/livedata/livedata_tests.js
@@ -187,25 +187,23 @@ testAsyncMulti("livedata - basic method invocation", [
 
 
 var checkBalances = function (a, b) {
-  var alice = Ledger.findOne({name: "alice", world: world});
-  var bob = Ledger.findOne({name: "bob", world: world});
+  var alice = Ledger.findOne({name: "alice", world: test.runId()});
+  var bob = Ledger.findOne({name: "bob", world: test.runId()});
   assert.equal(alice.balance, a);
   assert.equal(bob.balance, b);
 }
 
 // would be nice to have a database-aware test harness of some kind --
 // this is a big hack (and XXX pollutes the global test namespace)
-var world;
 testAsyncMulti("livedata - compound methods", [
   function () {
-    world = LocalCollection.uuid();
     if (Meteor.is_client)
-      Meteor.subscribe("ledger", {world: world});
-    Ledger.insert({name: "alice", balance: 100, world: world});
-    Ledger.insert({name: "bob", balance: 50, world: world});
+      Meteor.subscribe("ledger", {world: test.runId()});
+    Ledger.insert({name: "alice", balance: 100, world: test.runId()});
+    Ledger.insert({name: "bob", balance: 50, world: test.runId()});
   },
   function (expect) {
-    App.call('ledger/transfer', world, "alice", "bob", 10,
+    App.call('ledger/transfer', test.runId(), "alice", "bob", 10,
              expect(undefined, undefined));
 
     checkBalances(90, 60);
@@ -217,7 +215,7 @@ testAsyncMulti("livedata - compound methods", [
     });
   },
   function (expect) {
-    App.call('ledger/transfer', world, "alice", "bob", 100, true,
+    App.call('ledger/transfer', test.runId(), "alice", "bob", 100, true,
              expect(failure(409)));
 
     if (Meteor.is_client)
diff --git a/packages/tinytest/tinytest.js b/packages/tinytest/tinytest.js
index 34462f973f..7acf799f1b 100644
--- a/packages/tinytest/tinytest.js
+++ b/packages/tinytest/tinytest.js
@@ -80,6 +80,7 @@ Meteor._TestRun = function (manager, onReport) {
   self.current_fail_count = null;
   self.stop_at_offset = null;
   self.current_onException = null;
+  self.id = Meteor.uuid();
 
   _.each(self.manager.ordered_tests, _.bind(self._report, self));
 };
@@ -343,6 +344,12 @@ _.extend(globals.test, {
 
   exception: function (exception) {
     test._currentRun.get().exception(exception);
+  },
+
+  // returns a unique ID for this test run, for convenience use by
+  // your tests
+  runId: function () {
+    return test._currentRun.get().id;
   }
 });