diff -r 000000000000 -r 6474c204b198 addon-sdk/source/test/test-registry.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/test/test-registry.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+'use strict';
+
+exports['test:add'] = function(assert) {
+  function Class() {}
+  let fixture = require('sdk/util/registry').Registry(Class);
+  let isAddEmitted = false;
+  fixture.on('add', function(item) {
+    assert.ok(
+      item instanceof Class,
+      'if object added is not an instance should construct instance from it'
+    );
+    assert.ok(
+      fixture.has(item),
+      'callback is called after instance is added'
+    );
+    assert.ok(
+      !isAddEmitted,
+      'callback should be called for the same item only once'
+    );
+    isAddEmitted = true;
+  });
+
+  let object = fixture.add({});
+  fixture.add(object);
+};
+
+exports['test:remove'] = function(assert) {
+  function Class() {}
+  let fixture = require('sdk/util/registry').Registry(Class);
+  fixture.on('remove', function(item) {
+     assert.ok(
+      item instanceof Class,
+      'if object removed can be only instance of Class'
+    );
+    assert.ok(
+      fixture.has(item),
+      'callback is called before instance is removed'
+    );
+    assert.ok(
+      !isRemoveEmitted,
+      'callback should be called for the same item only once'
+    );
+    isRemoveEmitted = true;
+  });
+
+  fixture.remove({});
+  let object = fixture.add({});
+  fixture.remove(object);
+  fixture.remove(object);
+};
+
+exports['test:items'] = function(assert) {
+  function Class() {}
+  let fixture = require('sdk/util/registry').Registry(Class),
+      actual,
+      times = 0;
+
+  function testItem(item) {
+    times ++;
+    assert.equal(
+      actual,
+      item,
+      'item should match actual item being added/removed'
+    );
+  }
+  
+  actual = fixture.add({});
+
+  fixture.on('add', testItem);
+  fixture.on('remove', testItem);
+  
+  fixture.remove(actual);
+  fixture.remove(fixture.add(actual = new Class()));
+  assert.equal(3, times, 'should notify listeners on each call');
+};
+
+require('sdk/test').run(exports);
+