Bug 1192921: Add an install location for system add-ons. r=rhelmer

This adds two new directory install locations. One contains the default system
add-ons that ship with the application, the other contains system add-on that
will eventually be updatable at runtime.

The updatable location tracks the expected list of add-ons in a pref. and only
returns add-ons from that list when asked for its list of add-ons.

After processFileChanges has scanned all add-ons and updated the database it
checks if the updated system add-ons match the expected set. If not we ignore
those add-ons when working out which add-ons should be visible. If they do match
then we ignore the app-shipped system add-ons when working out which are
visible.

--HG--
extra : commitid : H1px7lWsLNj
extra : rebase_source : 6b70fd6c88608169e2974e19acd37bf63243c1cd

toolkit/mozapps/extensions/internal/XPIProvider.jsm

@@ -99,6 +99,7 @@ const PREF_INSTALL_DISTRO_ADDONS      = "extensions.installDistroAddons";
 const PREF_BRANCH_INSTALLED_ADDON     = "extensions.installedDistroAddon.";
 const PREF_SHOWN_SELECTION_UI         = "extensions.shownSelectionUI";
 const PREF_INTERPOSITION_ENABLED      = "extensions.interposition.enabled";
+const PREF_SYSTEM_ADDON_SET           = "extensions.systemAddonSet";
 
 const PREF_EM_MIN_COMPAT_APP_VERSION      = "extensions.minCompatibleAppVersion";
 const PREF_EM_MIN_COMPAT_PLATFORM_VERSION = "extensions.minCompatiblePlatformVersion";
@@ -116,6 +117,7 @@ const URI_EXTENSION_STRINGS           = "chrome://mozapps/locale/extensions/exte
 const STRING_TYPE_NAME                = "type.%ID%.name";
 
 const DIR_EXTENSIONS                  = "extensions";
+const DIR_SYSTEM_ADDONS               = "features";
 const DIR_STAGE                       = "staged";
 const DIR_TRASH                       = "trash";
 
@@ -131,6 +133,8 @@ const KEY_TEMPDIR                     = "TmpD";
 const KEY_APP_DISTRIBUTION            = "XREAppDist";
 
 const KEY_APP_PROFILE                 = "app-profile";
+const KEY_APP_SYSTEM_ADDONS           = "app-system-addons";
+const KEY_APP_SYSTEM_DEFAULTS         = "app-system-defaults";
 const KEY_APP_GLOBAL                  = "app-global";
 const KEY_APP_SYSTEM_LOCAL            = "app-system-local";
 const KEY_APP_SYSTEM_SHARE            = "app-system-share";
@@ -1957,7 +1961,7 @@ this.XPIStates = {
 
     for (let location of XPIProvider.installLocations) {
       // The list of add-on like file/directory names in the install location.
-      let addons = location.addonLocations;
+      let addons = location.getAddonLocations();
       // The results of scanning this location.
       let foundAddons = new SerializableMap();
 
@@ -2313,6 +2317,28 @@ this.XPIProvider = {
       XPIProvider.installLocationsByName[location.name] = location;
     }
 
+    function addSystemAddonInstallLocation(aName, aKey, aPaths, aScope) {
+      try {
+        var dir = FileUtils.getDir(aKey, aPaths);
+      }
+      catch (e) {
+        // Some directories aren't defined on some platforms, ignore them
+        logger.debug("Skipping unavailable install location " + aName);
+        return;
+      }
+
+      try {
+        var location = new SystemAddonInstallLocation(aName, dir, aScope, aAppChanged !== false);
+      }
+      catch (e) {
+        logger.warn("Failed to add system add-on install location " + aName, e);
+        return;
+      }
+
+      XPIProvider.installLocations.push(location);
+      XPIProvider.installLocationsByName[location.name] = location;
+    }
+
     function addRegistryInstallLocation(aName, aRootkey, aScope) {
       try {
         var location = new WinRegInstallLocation(aName, aRootkey, aScope);
@@ -2355,6 +2381,14 @@ this.XPIProvider = {
                                   [DIR_EXTENSIONS],
                                   AddonManager.SCOPE_PROFILE, false);
 
+      addSystemAddonInstallLocation(KEY_APP_SYSTEM_ADDONS, KEY_PROFILEDIR,
+                                    [DIR_SYSTEM_ADDONS],
+                                    AddonManager.SCOPE_PROFILE);
+
+      addDirectoryInstallLocation(KEY_APP_SYSTEM_DEFAULTS, KEY_APP_DISTRIBUTION,
+                                  [DIR_SYSTEM_ADDONS],
+                                  AddonManager.SCOPE_PROFILE, true);
+
       if (enabledScopes & AddonManager.SCOPE_USER) {
         addDirectoryInstallLocation(KEY_APP_SYSTEM_USER, "XREUSysExt",
                                     [Services.appinfo.ID],
@@ -6757,7 +6791,7 @@ function DirectoryInstallLocation(aName, aDirectory, aScope) {
   this._IDToFileMap = {};
   this._linkedAddons = [];
 
-  if (!aDirectory.exists())
+  if (!aDirectory || !aDirectory.exists())
     return;
   if (!aDirectory.isDirectory())
     throw new Error("Location must be a directory.");
@@ -6882,7 +6916,7 @@ DirectoryInstallLocation.prototype = {
   /**
    * Gets an array of nsIFiles for add-ons installed in this location.
    */
-  get addonLocations() {
+  getAddonLocations: function() {
     let locations = new Map();
     for (let id in this._IDToFileMap) {
       locations.set(id, this._IDToFileMap[id].clone());
@@ -7201,6 +7235,128 @@ Object.assign(MutableDirectoryInstallLocation.prototype, {
   },
 });
 
+/**
+ * An object which identifies a directory install location for system add-ons.
+ * The location consists of a directory which contains the add-ons installed in
+ * the location.
+ *
+ * @param  aName
+ *         The string identifier for the install location
+ * @param  aDirectory
+ *         The nsIFile directory for the install location
+ * @param  aScope
+ *         The scope of add-ons installed in this location
+ * @param  aResetSet
+ *         True to throw away the current add-on set
+ */
+function SystemAddonInstallLocation(aName, aDirectory, aScope, aResetSet) {
+  this._baseDir = aDirectory;
+
+  if (aResetSet) {
+    this._addonSet = { schema: 1, addons: {} };
+    this._saveAddonSet(this._addonSet);
+  }
+  else {
+    this._addonSet = this._loadAddonSet();
+  }
+
+  this._directory = null;
+  if (this._addonSet.directory) {
+    this._directory = aDirectory.clone();
+    this._directory.append(this._addonSet.directory);
+    logger.info("SystemAddonInstallLocation scanning directory " + this._directory.path);
+  }
+  else {
+    logger.info("SystemAddonInstallLocation directory is missing");
+  }
+
+  DirectoryInstallLocation.call(this, aName, this._directory, aScope);
+  this.locked = true;
+}
+
+SystemAddonInstallLocation.prototype = Object.create(DirectoryInstallLocation.prototype);
+Object.assign(SystemAddonInstallLocation.prototype, {
+  /**
+   * Reads the current set of system add-ons
+   */
+  _loadAddonSet: function() {
+    try {
+      let setStr = Preferences.get(PREF_SYSTEM_ADDON_SET, null);
+      if (setStr) {
+        let addonSet = JSON.parse(setStr);
+        if ((typeof addonSet == "object") && addonSet.schema == 1)
+          return addonSet;
+      }
+    }
+    catch (e) {
+      logger.error("Malformed system add-on set, resetting.");
+    }
+
+    return { schema: 1, addons: {} };
+  },
+
+  /**
+   * Saves the current set of system add-ons
+   */
+  _saveAddonSet: function(aAddonSet) {
+    Preferences.set(PREF_SYSTEM_ADDON_SET, JSON.stringify(aAddonSet));
+  },
+
+  getAddonLocations: function() {
+    let addons = DirectoryInstallLocation.prototype.getAddonLocations.call(this);
+
+    // Strip out any unexpected add-ons from the list
+    for (let id of addons.keys()) {
+      if (!(id in this._addonSet.addons))
+        addons.delete(id);
+    }
+
+    return addons;
+  },
+
+  /**
+   * Tests whether updated system add-ons are expected.
+   */
+  isActive: function() {
+    return this._directory != null;
+  },
+
+  /**
+   * Tests whether the loaded add-on information matches what is expected.
+   */
+  isValid: function(aAddons) {
+    for (let id of Object.keys(this._addonSet.addons)) {
+      if (!aAddons.has(id)) {
+        logger.warn("Expected add-on " + id + " is missing from the system add-on location.");
+        return false;
+      }
+
+      let addon = aAddons.get(id);
+      if (addon.appDisabled) {
+        logger.warn("System add-on " + id + " isn't compatible with the application.");
+        return false;
+      }
+
+      if (addon.unpack) {
+        logger.warn("System add-on " + id + " isn't a packed add-on.");
+        return false;
+      }
+
+      if (!addon.bootstrap) {
+        logger.warn("System add-on " + id + " isn't restartless.");
+        return false;
+      }
+
+      if (addon.version != this._addonSet.addons[id].version) {
+        logger.warn("System add-on " + id + " wasn't the correct version.");
+        return false;
+      }
+    }
+
+    return true;
+  },
+});
+
 #ifdef XP_WIN
 /**
  * An object that identifies a registry install location for add-ons. The location
@@ -7307,7 +7463,7 @@ WinRegInstallLocation.prototype = {
   /**
    * Gets an array of nsIFiles for add-ons installed in this location.
    */
-  get addonLocations() {
+  getAddonLocations: function() {
     let locations = new Map();
     for (let id in this._IDToFileMap) {
       locations.set(id, this._IDToFileMap[id].clone());

toolkit/mozapps/extensions/internal/XPIProviderUtils.js

@@ -1497,10 +1497,13 @@ this.XPIDatabaseReconcile = {
    * Returns a map of ID -> add-on. When the same add-on ID exists in multiple
    * install locations the highest priority location is chosen.
    */
-  flattenByID(addonMap) {
+  flattenByID(addonMap, hideLocation) {
     let map = new Map();
 
     for (let installLocation of XPIProvider.installLocations) {
+      if (installLocation.name == hideLocation)
+        continue;
+
       let locationMap = addonMap.get(installLocation.name);
       if (!locationMap)
         continue;
@@ -1608,7 +1611,12 @@ this.XPIDatabaseReconcile = {
     aNewAddon._installLocation = aInstallLocation;
     aNewAddon.installDate = aAddonState.mtime;
     aNewAddon.updateDate = aAddonState.mtime;
-    aNewAddon.foreignInstall = isDetectedInstall;
+
+    // Assume that add-ons in the system add-ons install location aren't
+    // foreign and should default to enabled.
+    aNewAddon.foreignInstall = isDetectedInstall &&
+                               aInstallLocation.name != KEY_APP_SYSTEM_ADDONS &&
+                               aInstallLocation.name != KEY_APP_SYSTEM_DEFAULTS;
 
     // appDisabled depends on whether the add-on is a foreignInstall so update
     aNewAddon.appDisabled = !isUsableAddon(aNewAddon);
@@ -1886,7 +1894,8 @@ this.XPIDatabaseReconcile = {
             // has changed
             let newAddon = loadedManifest(installLocation, id);
             if (newAddon || oldAddon.updateDate != xpiState.mtime ||
-                (aUpdateCompatibility && installLocation.name == KEY_APP_GLOBAL)) {
+                (aUpdateCompatibility && (installLocation.name == KEY_APP_GLOBAL ||
+                                          installLocation.name == KEY_APP_SYSTEM_DEFAULTS))) {
               newAddon = this.updateMetadata(installLocation, oldAddon, xpiState, newAddon);
             }
             else if (oldAddon.descriptor != xpiState.descriptor) {
@@ -1943,8 +1952,24 @@ this.XPIDatabaseReconcile = {
       }
     }
 
+    // Validate the updated system add-ons
+    let systemAddonLocation = XPIProvider.installLocationsByName[KEY_APP_SYSTEM_ADDONS];
+    let addons = currentAddons.get(KEY_APP_SYSTEM_ADDONS) || new Map();
+
+    let hideLocation;
+    if (systemAddonLocation.isActive() && systemAddonLocation.isValid(addons)) {
+      // Hide the system add-on defaults
+      logger.info("Hiding the default system add-ons.");
+      hideLocation = KEY_APP_SYSTEM_DEFAULTS;
+    }
+    else {
+      // Hide the system add-on updates
+      logger.info("Hiding the updated system add-ons.");
+      hideLocation = KEY_APP_SYSTEM_ADDONS;
+    }
+
     let previousVisible = this.getVisibleAddons(previousAddons);
-    let currentVisible = this.flattenByID(currentAddons);
+    let currentVisible = this.flattenByID(currentAddons, hideLocation);
     let sawActiveTheme = false;
     XPIProvider.bootstrappedAddons = {};
 
@@ -2012,11 +2037,9 @@ this.XPIDatabaseReconcile = {
           // and still exists then call its uninstall method.
           if (previousAddon.bootstrap && previousAddon._installLocation &&
               currentAddon._installLocation != previousAddon._installLocation &&
-              currentAddons.get(previousAddon._installLocation.name).has(id)) {
+              previousAddon._sourceBundle.exists()) {
 
-            let file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
-            file.persistentDescriptor = previousAddon._sourceBundle.persistentDescriptor;
-            XPIProvider.callBootstrapMethod(previousAddon, file,
+            XPIProvider.callBootstrapMethod(previousAddon, previousAddon._sourceBundle,
                                             "uninstall", installReason,
                                             { newVersion: currentAddon.version });
             XPIProvider.unloadBootstrapScope(previousAddon.id);
@@ -2071,6 +2094,15 @@ this.XPIDatabaseReconcile = {
       AddonManagerPrivate.addStartupChange(AddonManager.STARTUP_CHANGE_UNINSTALLED, id);
     }
 
+    // Make sure add-ons from hidden locations are marked invisible and inactive
+    let locationAddonMap = currentAddons.get(hideLocation);
+    if (locationAddonMap) {
+      for (let addon of locationAddonMap.values()) {
+        addon.visible = false;
+        addon.active = false;
+      }
+    }
+
     // None of the active add-ons match the selected theme, enable the default.
     if (!sawActiveTheme) {
       XPIProvider.enableDefaultTheme();

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app1/features/system_1_1/bootstrap.js

@@ -0,0 +1,18 @@
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+const ID = "system1@tests.mozilla.org";
+const VERSION = "1.0";
+
+function install(data, reason) {
+}
+
+function startup(data, reason) {
+  Services.prefs.setCharPref("bootstraptest." + ID + ".active_version", VERSION);
+}
+
+function shutdown(data, reason) {
+  Services.prefs.clearUserPref("bootstraptest." + ID + ".active_version");
+}
+
+function uninstall(data, reason) {
+}

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app1/features/system_1_1/install.rdf

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+
+<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
+
+  <Description about="urn:mozilla:install-manifest">
+    <em:id>system1@tests.mozilla.org</em:id>
+    <em:version>1.0</em:version>
+    <em:bootstrap>true</em:bootstrap>
+
+    <!-- Front End MetaData -->
+    <em:name>System Add-on 1</em:name>
+
+    <em:targetApplication>
+      <Description>
+        <em:id>xpcshell@tests.mozilla.org</em:id>
+        <em:minVersion>1</em:minVersion>
+        <em:maxVersion>5</em:maxVersion>
+      </Description>
+    </em:targetApplication>
+
+  </Description>
+</RDF>

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app1/features/system_2_1/bootstrap.js

@@ -0,0 +1,18 @@
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+const ID = "system2@tests.mozilla.org";
+const VERSION = "1.0";
+
+function install(data, reason) {
+}
+
+function startup(data, reason) {
+  Services.prefs.setCharPref("bootstraptest." + ID + ".active_version", VERSION);
+}
+
+function shutdown(data, reason) {
+  Services.prefs.clearUserPref("bootstraptest." + ID + ".active_version");
+}
+
+function uninstall(data, reason) {
+}

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app1/features/system_2_1/install.rdf

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+
+<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
+
+  <Description about="urn:mozilla:install-manifest">
+    <em:id>system2@tests.mozilla.org</em:id>
+    <em:version>1.0</em:version>
+    <em:bootstrap>true</em:bootstrap>
+
+    <!-- Front End MetaData -->
+    <em:name>System Add-on 2</em:name>
+
+    <em:targetApplication>
+      <Description>
+        <em:id>xpcshell@tests.mozilla.org</em:id>
+        <em:minVersion>1</em:minVersion>
+        <em:maxVersion>5</em:maxVersion>
+      </Description>
+    </em:targetApplication>
+
+  </Description>
+</RDF>

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app2/features/system_1_2/bootstrap.js

@@ -0,0 +1,18 @@
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+const ID = "system1@tests.mozilla.org";
+const VERSION = "2.0";
+
+function install(data, reason) {
+}
+
+function startup(data, reason) {
+  Services.prefs.setCharPref("bootstraptest." + ID + ".active_version", VERSION);
+}
+
+function shutdown(data, reason) {
+  Services.prefs.clearUserPref("bootstraptest." + ID + ".active_version");
+}
+
+function uninstall(data, reason) {
+}

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app2/features/system_1_2/install.rdf

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+
+<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
+
+  <Description about="urn:mozilla:install-manifest">
+    <em:id>system1@tests.mozilla.org</em:id>
+    <em:version>2.0</em:version>
+    <em:bootstrap>true</em:bootstrap>
+
+    <!-- Front End MetaData -->
+    <em:name>System Add-on 1</em:name>
+
+    <em:targetApplication>
+      <Description>
+        <em:id>xpcshell@tests.mozilla.org</em:id>
+        <em:minVersion>1</em:minVersion>
+        <em:maxVersion>5</em:maxVersion>
+      </Description>
+    </em:targetApplication>
+
+  </Description>
+</RDF>

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app2/features/system_3_1/bootstrap.js

@@ -0,0 +1,18 @@
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+const ID = "system3@tests.mozilla.org";
+const VERSION = "1.0";
+
+function install(data, reason) {
+}
+
+function startup(data, reason) {
+  Services.prefs.setCharPref("bootstraptest." + ID + ".active_version", VERSION);
+}
+
+function shutdown(data, reason) {
+  Services.prefs.clearUserPref("bootstraptest." + ID + ".active_version");
+}
+
+function uninstall(data, reason) {
+}

toolkit/mozapps/extensions/test/xpcshell/data/system_addons/app2/features/system_3_1/install.rdf

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+
+<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
+
+  <Description about="urn:mozilla:install-manifest">
+    <em:id>system3@tests.mozilla.org</em:id>
+    <em:version>1.0</em:version>
+    <em:bootstrap>true</em:bootstrap>
+
+    <!-- Front End MetaData -->
+    <em:name>System Add-on 3</em:name>
+
+    <em:targetApplication>
+      <Description>
+        <em:id>xpcshell@tests.mozilla.org</em:id>
+        <em:minVersion>1</em:minVersion>
+        <em:maxVersion>5</em:maxVersion>
+      </Description>
+    </em:targetApplication>
+
+  </Description>
+</RDF>

toolkit/mozapps/extensions/test/xpcshell/head_addons.js

@@ -1026,7 +1026,7 @@ function getFileForAddon(aDir, aId) {
 function registerDirectory(aKey, aDir) {
   var dirProvider = {
     getFile: function(aProp, aPersistent) {
-      aPersistent.value = true;
+      aPersistent.value = false;
       if (aProp == aKey)
         return aDir.clone();
       return null;

toolkit/mozapps/extensions/test/xpcshell/test_system_reset.js

@@ -0,0 +1,200 @@
+// Tests that we reset to the default system add-ons correctly when switching
+// application versions
+const PREF_SYSTEM_ADDON_SET = "extensions.systemAddonSet";
+
+const featureDir = gProfD.clone();
+featureDir.append("features");
+
+const distroDir = do_get_file("data/system_addons/app0");
+registerDirectory("XREAppDist", distroDir);
+
+createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "0");
+
+function makeUUID() {
+  let uuidGen = AM_Cc["@mozilla.org/uuid-generator;1"].
+                getService(AM_Ci.nsIUUIDGenerator);
+  return uuidGen.generateUUID().toString();
+}
+
+function* check_installed(inProfile, ...versions) {
+  let expectedDir;
+  if (inProfile) {
+    expectedDir = featureDir;
+  }
+  else {
+    expectedDir = distroDir.clone();
+    expectedDir.append("features");
+  }
+
+  for (let i = 0; i < versions.length; i++) {
+    let id = "system" + (i + 1) + "@tests.mozilla.org";
+    let addon = yield promiseAddonByID(id);
+
+    if (versions[i]) {
+      // Add-on should be installed
+      do_check_neq(addon, null);
+      do_check_eq(addon.version, versions[i]);
+      do_check_true(addon.isActive);
+      do_check_false(addon.foreignInstall);
+
+      // Verify the add-ons file is in the right place
+      let file = expectedDir.clone();
+      file.append(id + ".xpi");
+      do_check_true(file.exists());
+      do_check_true(file.isFile());
+
+      let uri = addon.getResourceURI(null);
+      do_check_true(uri instanceof AM_Ci.nsIFileURL);
+      do_check_eq(uri.file.path, file.path);
+
+      // Verify the add-on actually started
+      let installed = Services.prefs.getCharPref("bootstraptest." + id + ".active_version");
+      do_check_eq(installed, versions[i]);
+    }
+    else {
+      // Add-on should not be installed
+      do_check_eq(addon, null);
+
+      try {
+        Services.prefs.getCharPref("bootstraptest." + id + ".active_version");
+        do_throw("Expected pref to be missing");
+      }
+      catch (e) {
+      }
+    }
+  }
+}
+
+// Test with a missing features directory
+add_task(function* test_missing_app_dir() {
+  startupManager();
+
+  yield check_installed(false, null, null, null);
+
+  do_check_false(featureDir.exists());
+
+  yield promiseShutdownManager();
+});
+
+// Add some features in a new version
+add_task(function* test_new_version() {
+  gAppInfo.version = "1";
+  distroDir.leafName = "app1";
+  startupManager();
+
+  yield check_installed(false, "1.0", "1.0", null);
+
+  do_check_false(featureDir.exists());
+
+  yield promiseShutdownManager();
+});
+
+// Another new version swaps one feature and upgrades another
+add_task(function* test_upgrade() {
+  gAppInfo.version = "2";
+  distroDir.leafName = "app2";
+  startupManager();
+
+  yield check_installed(false, "2.0", null, "1.0");
+
+  do_check_false(featureDir.exists());
+
+  yield promiseShutdownManager();
+});
+
+// Downgrade
+add_task(function* test_downgrade() {
+  gAppInfo.version = "1";
+  distroDir.leafName = "app1";
+  startupManager();
+
+  yield check_installed(false, "1.0", "1.0", null);
+
+  do_check_false(featureDir.exists());
+
+  yield promiseShutdownManager();
+});
+
+// Fake a mid-cycle install
+add_task(function* test_updated() {
+  // Create a random dir to install into
+  let dirname = makeUUID();
+  FileUtils.getDir("ProfD", ["features", dirname], true);
+  featureDir.append(dirname);
+
+  // Copy in the system add-ons
+  let file = do_get_file("data/system_addons/app1/features/system2@tests.mozilla.org.xpi");
+  file.copyTo(featureDir, file.leafName);
+  file = do_get_file("data/system_addons/app2/features/system3@tests.mozilla.org.xpi");
+  file.copyTo(featureDir, file.leafName);
+
+  // Inject it into the system set
+  let addonSet = {
+    schema: 1,
+    directory: dirname,
+    addons: {
+      "system2@tests.mozilla.org": {
+        version: "1.0"
+      },
+      "system3@tests.mozilla.org": {
+        version: "1.0"
+      },
+    }
+  };
+  Services.prefs.setCharPref(PREF_SYSTEM_ADDON_SET, JSON.stringify(addonSet));
+
+  startupManager(false);
+
+  yield check_installed(true, null, "1.0", "1.0");
+
+  yield promiseShutdownManager();
+});
+
+// An additional add-on in the directory should be ignored
+add_task(function* test_skips_additional() {
+  // Copy in the system add-ons
+  let file = do_get_file("data/system_addons/app1/features/system1@tests.mozilla.org.xpi");
+  file.copyTo(featureDir, file.leafName);
+
+  startupManager(false);
+
+  yield check_installed(true, null, "1.0", "1.0");
+
+  yield promiseShutdownManager();
+});
+
+// Missing add-on should revert to the default set
+add_task(function* test_revert() {
+  manuallyUninstall(featureDir, "system2@tests.mozilla.org");
+
+  startupManager(false);
+
+  // With system add-on 2 gone the updated set is now invalid so it reverts to
+  // the default set which is system add-ons 1 and 2.
+  yield check_installed(false, "1.0", "1.0", null);
+
+  yield promiseShutdownManager();
+});
+
+// Putting it back will make the set work again
+add_task(function* test_reuse() {
+  let file = do_get_file("data/system_addons/app1/features/system2@tests.mozilla.org.xpi");
+  file.copyTo(featureDir, file.leafName);
+
+  startupManager(false);
+
+  yield check_installed(true, null, "1.0", "1.0");
+
+  yield promiseShutdownManager();
+});
+
+// Making the pref corrupt should revert to the default set
+add_task(function* test_corrupt_pref() {
+  Services.prefs.setCharPref(PREF_SYSTEM_ADDON_SET, "foo");
+
+  startupManager(false);
+
+  yield check_installed(false, "1.0", "1.0", null);
+
+  yield promiseShutdownManager();
+});

toolkit/mozapps/extensions/test/xpcshell/xpcshell.ini

@@ -24,6 +24,7 @@ skip-if = appname != "firefox"
 [test_provider_unsafe_access_shutdown.js]
 [test_provider_unsafe_access_startup.js]
 [test_shutdown.js]
+[test_system_reset.js]
 [test_XPIcancel.js]
 [test_XPIStates.js]