diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/registration/DynamicSet.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/registration/DynamicSet.java
index 628745a225..380cfc67ec 100644
--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/registration/DynamicSet.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/registration/DynamicSet.java
@@ -139,6 +139,10 @@ public class DynamicSet<T> implements Iterable<T> {
     items = new CopyOnWriteArrayList<>(base);
   }
 
+  public DynamicSet() {
+    this(Collections.<AtomicReference<Provider<T>>>emptySet());
+  }
+
   @Override
   public Iterator<T> iterator() {
     final Iterator<AtomicReference<Provider<T>>> itr = items.iterator();
diff --git a/gerrit-server/src/test/java/com/google/gerrit/server/account/UniversalGroupBackendTest.java b/gerrit-server/src/test/java/com/google/gerrit/server/account/UniversalGroupBackendTest.java
new file mode 100644
index 0000000000..00e6d01957
--- /dev/null
+++ b/gerrit-server/src/test/java/com/google/gerrit/server/account/UniversalGroupBackendTest.java
@@ -0,0 +1,148 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.account;
+
+import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
+import static com.google.gerrit.server.group.SystemGroupBackend.PROJECT_OWNERS;
+import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+import static org.easymock.EasyMock.anyObject;
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.createNiceMock;
+import static org.easymock.EasyMock.eq;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.getCurrentArguments;
+import static org.easymock.EasyMock.not;
+import static org.easymock.EasyMock.replay;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gerrit.extensions.registration.DynamicSet;
+import com.google.gerrit.reviewdb.client.AccountGroup;
+import com.google.gerrit.reviewdb.client.AccountGroup.UUID;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.group.SystemGroupBackend;
+import com.google.gwtorm.client.KeyUtil;
+import com.google.gwtorm.server.StandardKeyEncoder;
+
+import org.easymock.IAnswer;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Set;
+
+public class UniversalGroupBackendTest {
+  static {
+    KeyUtil.setEncoderImpl(new StandardKeyEncoder());
+  }
+
+  private static final AccountGroup.UUID OTHER_UUID =
+      new AccountGroup.UUID("other");
+
+  private UniversalGroupBackend backend;
+  private IdentifiedUser user;
+
+  private DynamicSet<GroupBackend> backends;
+
+  @Before
+  public void setup() {
+    user = createNiceMock(IdentifiedUser.class);
+    replay(user);
+    backends = new DynamicSet<GroupBackend>();
+    backends.add(new SystemGroupBackend());
+    backend = new UniversalGroupBackend(backends);
+  }
+
+  @Test
+  public void testHandles() {
+    assertTrue(backend.handles(ANONYMOUS_USERS));
+    assertTrue(backend.handles(PROJECT_OWNERS));
+    assertFalse(backend.handles(OTHER_UUID));
+  }
+
+  @Test
+  public void testGet() {
+    assertEquals("Registered Users",
+        backend.get(REGISTERED_USERS).getName());
+    assertEquals("Project Owners",
+        backend.get(PROJECT_OWNERS).getName());
+    assertNull(backend.get(OTHER_UUID));
+  }
+
+  @Test
+  public void testSuggest() {
+    assertTrue(backend.suggest("X", null).isEmpty());
+    assertEquals(1, backend.suggest("project", null).size());
+    assertEquals(1, backend.suggest("reg", null).size());
+  }
+
+  @Test
+  public void testSytemGroupMemberships() {
+    GroupMembership checker = backend.membershipsOf(user);
+    assertTrue(checker.contains(REGISTERED_USERS));
+    assertFalse(checker.contains(OTHER_UUID));
+    assertFalse(checker.contains(PROJECT_OWNERS));
+  }
+
+  @Test
+  public void testKnownGroups() {
+    GroupMembership checker = backend.membershipsOf(user);
+    Set<UUID> knownGroups = checker.getKnownGroups();
+    assertEquals(2, knownGroups.size());
+    assertTrue(knownGroups.contains(REGISTERED_USERS));
+    assertTrue(knownGroups.contains(ANONYMOUS_USERS));
+  }
+
+  @Test
+  public void testOtherMemberships() {
+    final AccountGroup.UUID handled = new AccountGroup.UUID("handled");
+    final AccountGroup.UUID notHandled = new AccountGroup.UUID("not handled");
+    final IdentifiedUser member = createNiceMock(IdentifiedUser.class);
+    final IdentifiedUser notMember = createNiceMock(IdentifiedUser.class);
+
+    GroupBackend backend = createMock(GroupBackend.class);
+    expect(backend.handles(handled)).andStubReturn(true);
+    expect(backend.handles(not(eq(handled)))).andStubReturn(false);
+    expect(backend.membershipsOf(anyObject(IdentifiedUser.class)))
+        .andStubAnswer(new IAnswer<GroupMembership>() {
+          @Override
+          public GroupMembership answer() throws Throwable {
+            Object[] args = getCurrentArguments();
+            GroupMembership membership = createMock(GroupMembership.class);
+            expect(membership.contains(eq(handled))).andStubReturn(args[0] == member);
+            expect(membership.contains(not(eq(notHandled)))).andStubReturn(false);
+            replay(membership);
+            return membership;
+          }
+        });
+    replay(member, notMember, backend);
+
+    backends = new DynamicSet<GroupBackend>();
+    backends.add(backend);
+    backend = new UniversalGroupBackend(backends);
+
+    GroupMembership checker =
+        backend.membershipsOf(member);
+    assertFalse(checker.contains(REGISTERED_USERS));
+    assertFalse(checker.contains(OTHER_UUID));
+    assertTrue(checker.contains(handled));
+    assertFalse(checker.contains(notHandled));
+    checker = backend.membershipsOf(notMember);
+    assertFalse(checker.contains(handled));
+    assertFalse(checker.contains(notHandled));
+  }
+
+}