Issue 6775 - Work around filter data stored in IndexedDB getting lost on Microsoft Edge

qunit/tests/indexedDBBackup.js

Index: qunit/tests/indexedDBBackup.js
diff --git a/qunit/tests/indexedDBBackup.js b/qunit/tests/indexedDBBackup.js
new file mode 100644
index 0000000000000000000000000000000000000000..0003a0550b14b7e535a8664d9daa4f8bab415157
--- /dev/null
+++ b/qunit/tests/indexedDBBackup.js
@@ -0,0 +1,140 @@
+"use strict";
+
+{
+  const {IndexedDBBackup} = require("../../lib/indexedDBBackup");
+  const info = require("info");
+  const {FilterStorage} = require("../../adblockpluscore/lib/filterStorage");
+  const {Filter} = require("../../adblockpluscore/lib/filterClasses");
+  const {Subscription, SpecialSubscription} =
+    require("../../adblockpluscore/lib/subscriptionClasses");
+
+  let writeTime = 0;
+  let writeInterval = 100;
+  let subscription = Subscription.fromObject({
+    title: "test",
+    url: "test.com",
+    homepage: "example.com",
+    lastSuccess: 8,
+    disabled: false,
+    lastDownload: 12,
+    lastCheck: 16,
+    softExpiration: 18,
+    expires: 20,
+    downloadStatus: "done",
+    errors: 3,
+    version: 24,
+    downloadCount: 1,
+    requiredVersion: "0.6"
+  });
+  let filter = Filter.fromText("example.com");
+  let specialSubscription = SpecialSubscription.createForFilter(filter);
+
+  let testEdge = info.platform == "edgehtml" ? QUnit.test : QUnit.skip;
+
+  QUnit.module("Microsoft Edge indexedDB backup", {
+    beforeEach()
+    {
+      this._storageLocalSet = browser.storage.local.set;
+      IndexedDBBackup.init(writeInterval);
+    },
+    afterEach()
+    {
+      Object.defineProperty(
+        browser.storage.local, "set",
+        {value: this._storageLocalSet, enumerable: true});
+      IndexedDBBackup.init();
+    }
+  });
+
+  testEdge("Write time smaller than backup interval", assert =>
+  {
+    writeTime = 10;
+    testSaveSteps(assert);
+  });
+
+  testEdge("Write time greater than backup interval", assert =>
+  {
+    writeTime = 150;
+    testSaveSteps(assert);
+  });
+
+  function testSaveSteps(assert)
+  {
+    let start = performance.now();
+    let saveTimes = [];
+
+    let steps = [
+      {
+        done: assert.async(),
+        check(data)
+        {
+          let expectedFormat = [
+            "[Subscription]",
+            `url=${specialSubscription.url}`,
+            "defaults=blocking",
+            "[Subscription filters]",
+            "example.com"
+          ];
+          ok(start - data.lastModified < writeInterval,
+            "first change is proccessed immediately");
+          deepEqual(
+            data.content, expectedFormat, "data is formatted correctly");
+        }
+      },
+      {
+        done: assert.async(),
+        check(data)
+        {
+          let expectedFormat = [
+            "[Subscription]",
+            `url=${specialSubscription.url}`,
+            "defaults=blocking",
+            "[Subscription filters]",
+            "example.com",
+            "[Subscription]",
+            "homepage=example.com",
+            "title=test",
+            "url=test.com",
+            "disabled=false"
+          ];
+          ok(data.lastModified - saveTimes[0] >= writeInterval,
+            "next change is after the time limit");
+          deepEqual(
+            data.content, expectedFormat, "data is formatted correctly");
+
+          FilterStorage.removeSubscription(subscription);
+          FilterStorage.removeSubscription(specialSubscription);
+        }
+      },
+      {
+        done: assert.async(),
+        check(data)
+        {
+          deepEqual(
+            data.content, [], "multiple changes are treated in one write");
+        }
+      }
+    ];
+    let mockSave = (data) =>
+    {
+      return new Promise(resolve =>
+      {
+        setTimeout(() =>
+        {
+          saveTimes.push(performance.now());
+          let step = steps.shift();
+          step.check(data["file:indexedDB-backup"]);
+          step.done();
+          resolve();
+        }, writeTime);
+      });
+    };
+
+    Object.defineProperty(
+      browser.storage.local, "set",
+      {value: mockSave, enumerable: true});
+
+    FilterStorage.addSubscription(specialSubscription);
+    FilterStorage.addSubscription(subscription);
+  }
+}