Index: test/filterStorage_readwrite.js
===================================================================
--- a/test/filterStorage_readwrite.js
+++ b/test/filterStorage_readwrite.js
@@ -106,17 +106,17 @@
     if (withExternal)
     {
       {
         let subscription = new ExternalSubscription("~external~external subscription ID", "External subscription");
         subscription.filters = [Filter.fromText("foo"), Filter.fromText("bar")];
         FilterStorage.addSubscription(subscription);
       }
 
-      let externalSubscriptions = FilterStorage.subscriptions.filter(subscription => subscription instanceof ExternalSubscription);
+      let externalSubscriptions = [...FilterStorage.subscriptions()].filter(subscription => subscription instanceof ExternalSubscription);
       test.equal(externalSubscriptions.length, 1, "Number of external subscriptions after updateExternalSubscription");
 
       test.equal(externalSubscriptions[0].url, "~external~external subscription ID", "ID of external subscription");
       test.equal(externalSubscriptions[0].filters.length, 2, "Number of filters in external subscription");
     }
 
     return FilterStorage.saveToDisk();
   }).then(() => testData).then(expected =>
@@ -225,28 +225,28 @@
 
 exports.testRestoringBackup = function(test)
 {
   Prefs.patternsbackups = 2;
   Prefs.patternsbackupinterval = 24;
 
   FilterStorage.saveToDisk().then(() =>
   {
-    test.equal(FilterStorage.subscriptions[0].filters.length, 1, "Initial filter count");
+    test.equal([...FilterStorage.subscriptions()][0].filters.length, 1, "Initial filter count");
     FilterStorage.addFilter(Filter.fromText("barfoo"));
-    test.equal(FilterStorage.subscriptions[0].filters.length, 2, "Filter count after adding a filter");
+    test.equal([...FilterStorage.subscriptions()][0].filters.length, 2, "Filter count after adding a filter");
     return FilterStorage.saveToDisk();
   }).then(() =>
   {
     return FilterStorage.loadFromDisk();
   }).then(() =>
   {
-    test.equal(FilterStorage.subscriptions[0].filters.length, 2, "Filter count after adding filter and reloading");
+    test.equal([...FilterStorage.subscriptions()][0].filters.length, 2, "Filter count after adding filter and reloading");
     return FilterStorage.restoreBackup(1);
   }).then(() =>
   {
-    test.equal(FilterStorage.subscriptions[0].filters.length, 1, "Filter count after restoring backup");
+    test.equal([...FilterStorage.subscriptions()][0].filters.length, 1, "Filter count after restoring backup");
     return FilterStorage.loadFromDisk();
   }).then(() =>
   {
-    test.equal(FilterStorage.subscriptions[0].filters.length, 1, "Filter count after reloading");
+    test.equal([...FilterStorage.subscriptions()][0].filters.length, 1, "Filter count after reloading");
   }).catch(unexpectedError.bind(test)).then(() => test.done());
 };