Teach the network simulator to wait for Promises.

Tools/GardeningServer/model/test/tree-status-tests.html

Index: Tools/GardeningServer/model/test/tree-status-tests.html
diff --git a/Tools/GardeningServer/model/test/tree-status-tests.html b/Tools/GardeningServer/model/test/tree-status-tests.html
index b79a5a43801c9e6457dd2c6cbbaca86f90a97928..85deef415d735afe1f204794279f3011c21d8667 100644
--- a/Tools/GardeningServer/model/test/tree-status-tests.html
+++ b/Tools/GardeningServer/model/test/tree-status-tests.html
@@ -53,7 +53,7 @@ describe('tree status', function() {
     };
 
     simulator.runTest(function() {
-      Promise.all([
+      return Promise.all([
         opentree.update().then(function() {
           assert.equal(opentree.status, 'open');
         }),
@@ -68,7 +68,7 @@ describe('tree status', function() {
           assert.equal(closedtree.status, "closed");
         })
       ]);
-    }).then(done);
+    });
   });
 });