diff --git a/android/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java b/android/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java
new file mode 100644
index 000000000000..8a783ec6e823
--- /dev/null
+++ b/android/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredCollectionTest;
+import java.util.Collection;
+
+public final class Collections2FilterArrayListTest
+    extends AbstractFilteredCollectionTest<Collection<Integer>> {
+  @Override
+  Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Lists.newArrayList(contents);
+  }
+
+  @Override
+  Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {
+    return Collections2.filter(elements, predicate);
+  }
+}
diff --git a/android/guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java b/android/guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
similarity index 82%
rename from android/guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java
rename to android/guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
index 3b05972eeeec..77e01dc5836a 100644
--- a/android/guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java
+++ b/android/guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
@@ -28,15 +28,19 @@
 import java.util.NoSuchElementException;
 import java.util.Set;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import junit.framework.TestCase;
 
 /**
- * Tests for filtered collection views.
+ * Class that contains nested abstract tests for filtered collection views, along with their
+ * implementation helpers.
  *
  * @author Louis Wasserman
  */
-public class FilteredCollectionsTest extends TestCase {
+/*
+ * TODO(cpovirk): Should all the tests for filtered collections run under GWT, too? Currently, they
+ * don't.
+ */
+public final class FilteredCollectionsTestUtil {
   private static final Predicate<Integer> EVEN =
       new Predicate<Integer>() {
         @Override
@@ -374,79 +378,5 @@ public void testNavigation() {
     }
   }
 
-  // implementation tests
-
-  public static final class IterablesFilterArrayListTest
-      extends AbstractFilteredIterableTest<Iterable<Integer>> {
-    @Override
-    Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Lists.newArrayList(contents);
-    }
-
-    @Override
-    Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
-      return Iterables.filter(elements, predicate);
-    }
-  }
-
-  public static final class Collections2FilterArrayListTest
-      extends AbstractFilteredCollectionTest<Collection<Integer>> {
-    @Override
-    Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Lists.newArrayList(contents);
-    }
-
-    @Override
-    Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {
-      return Collections2.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
-    @Override
-    Set<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Sets.newHashSet(contents);
-    }
-
-    @Override
-    Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterSortedSetTest
-      extends AbstractFilteredSortedSetTest<SortedSet<Integer>> {
-    @Override
-    SortedSet<Integer> createUnfiltered(Iterable<Integer> contents) {
-      final TreeSet<Integer> result = Sets.newTreeSet(contents);
-      // we have to make the result not Navigable
-      return new ForwardingSortedSet<Integer>() {
-        @Override
-        protected SortedSet<Integer> delegate() {
-          return result;
-        }
-      };
-    }
-
-    @Override
-    SortedSet<Integer> filter(SortedSet<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterNavigableSetTest extends AbstractFilteredNavigableSetTest {
-    @Override
-    NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Sets.newTreeSet(contents);
-    }
-
-    @Override
-    NavigableSet<Integer> filter(
-        NavigableSet<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  /** No-op test so that the class has at least one method, making Maven's test runner happy. */
-  public void testNoop() {}
+  private FilteredCollectionsTestUtil() {}
 }
diff --git a/android/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java b/android/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java
new file mode 100644
index 000000000000..9cd2d90917c6
--- /dev/null
+++ b/android/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredIterableTest;
+
+public final class IterablesFilterArrayListTest
+    extends AbstractFilteredIterableTest<Iterable<Integer>> {
+  @Override
+  Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Lists.newArrayList(contents);
+  }
+
+  @Override
+  Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
+    return Iterables.filter(elements, predicate);
+  }
+}
diff --git a/android/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java b/android/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java
new file mode 100644
index 000000000000..a550f04875e5
--- /dev/null
+++ b/android/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredSetTest;
+import java.util.Set;
+
+public final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
+  @Override
+  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Sets.newHashSet(contents);
+  }
+
+  @Override
+  Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}
diff --git a/android/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java b/android/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java
new file mode 100644
index 000000000000..350c091507ba
--- /dev/null
+++ b/android/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredNavigableSetTest;
+import java.util.NavigableSet;
+
+public final class SetsFilterNavigableSetTest extends AbstractFilteredNavigableSetTest {
+  @Override
+  NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Sets.newTreeSet(contents);
+  }
+
+  @Override
+  NavigableSet<Integer> filter(
+      NavigableSet<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}
diff --git a/android/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java b/android/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java
new file mode 100644
index 000000000000..0529bead6ccd
--- /dev/null
+++ b/android/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredSortedSetTest;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+public final class SetsFilterSortedSetTest
+    extends AbstractFilteredSortedSetTest<SortedSet<Integer>> {
+  @Override
+  SortedSet<Integer> createUnfiltered(Iterable<Integer> contents) {
+    final TreeSet<Integer> result = Sets.newTreeSet(contents);
+    // we have to make the result not Navigable
+    return new ForwardingSortedSet<Integer>() {
+      @Override
+      protected SortedSet<Integer> delegate() {
+        return result;
+      }
+    };
+  }
+
+  @Override
+  SortedSet<Integer> filter(SortedSet<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}
diff --git a/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java b/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java
new file mode 100644
index 000000000000..8a783ec6e823
--- /dev/null
+++ b/guava-tests/test/com/google/common/collect/Collections2FilterArrayListTest.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredCollectionTest;
+import java.util.Collection;
+
+public final class Collections2FilterArrayListTest
+    extends AbstractFilteredCollectionTest<Collection<Integer>> {
+  @Override
+  Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Lists.newArrayList(contents);
+  }
+
+  @Override
+  Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {
+    return Collections2.filter(elements, predicate);
+  }
+}
diff --git a/guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java b/guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
similarity index 83%
rename from guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java
rename to guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
index 85b4e214d3d5..95bfac5bcb16 100644
--- a/guava-tests/test/com/google/common/collect/FilteredCollectionsTest.java
+++ b/guava-tests/test/com/google/common/collect/FilteredCollectionsTestUtil.java
@@ -29,15 +29,19 @@
 import java.util.NoSuchElementException;
 import java.util.Set;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import junit.framework.TestCase;
 
 /**
- * Tests for filtered collection views.
+ * Class that contains nested abstract tests for filtered collection views, along with their
+ * implementation helpers.
  *
  * @author Louis Wasserman
  */
-public class FilteredCollectionsTest extends TestCase {
+/*
+ * TODO(cpovirk): Should all the tests for filtered collections run under GWT, too? Currently, they
+ * don't.
+ */
+public final class FilteredCollectionsTestUtil {
   private static final Predicate<Integer> EVEN =
       new Predicate<Integer>() {
         @Override
@@ -389,79 +393,5 @@ public void testNavigation() {
     }
   }
 
-  // implementation tests
-
-  public static final class IterablesFilterArrayListTest
-      extends AbstractFilteredIterableTest<Iterable<Integer>> {
-    @Override
-    Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Lists.newArrayList(contents);
-    }
-
-    @Override
-    Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
-      return Iterables.filter(elements, predicate);
-    }
-  }
-
-  public static final class Collections2FilterArrayListTest
-      extends AbstractFilteredCollectionTest<Collection<Integer>> {
-    @Override
-    Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Lists.newArrayList(contents);
-    }
-
-    @Override
-    Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {
-      return Collections2.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
-    @Override
-    Set<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Sets.newHashSet(contents);
-    }
-
-    @Override
-    Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterSortedSetTest
-      extends AbstractFilteredSortedSetTest<SortedSet<Integer>> {
-    @Override
-    SortedSet<Integer> createUnfiltered(Iterable<Integer> contents) {
-      final TreeSet<Integer> result = Sets.newTreeSet(contents);
-      // we have to make the result not Navigable
-      return new ForwardingSortedSet<Integer>() {
-        @Override
-        protected SortedSet<Integer> delegate() {
-          return result;
-        }
-      };
-    }
-
-    @Override
-    SortedSet<Integer> filter(SortedSet<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  public static final class SetsFilterNavigableSetTest extends AbstractFilteredNavigableSetTest {
-    @Override
-    NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
-      return Sets.newTreeSet(contents);
-    }
-
-    @Override
-    NavigableSet<Integer> filter(
-        NavigableSet<Integer> elements, Predicate<? super Integer> predicate) {
-      return Sets.filter(elements, predicate);
-    }
-  }
-
-  /** No-op test so that the class has at least one method, making Maven's test runner happy. */
-  public void testNoop() {}
+  private FilteredCollectionsTestUtil() {}
 }
diff --git a/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java b/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java
new file mode 100644
index 000000000000..9cd2d90917c6
--- /dev/null
+++ b/guava-tests/test/com/google/common/collect/IterablesFilterArrayListTest.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredIterableTest;
+
+public final class IterablesFilterArrayListTest
+    extends AbstractFilteredIterableTest<Iterable<Integer>> {
+  @Override
+  Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Lists.newArrayList(contents);
+  }
+
+  @Override
+  Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
+    return Iterables.filter(elements, predicate);
+  }
+}
diff --git a/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java b/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java
new file mode 100644
index 000000000000..a550f04875e5
--- /dev/null
+++ b/guava-tests/test/com/google/common/collect/SetsFilterHashSetTest.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredSetTest;
+import java.util.Set;
+
+public final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
+  @Override
+  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Sets.newHashSet(contents);
+  }
+
+  @Override
+  Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}
diff --git a/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java b/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java
new file mode 100644
index 000000000000..350c091507ba
--- /dev/null
+++ b/guava-tests/test/com/google/common/collect/SetsFilterNavigableSetTest.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredNavigableSetTest;
+import java.util.NavigableSet;
+
+public final class SetsFilterNavigableSetTest extends AbstractFilteredNavigableSetTest {
+  @Override
+  NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
+    return Sets.newTreeSet(contents);
+  }
+
+  @Override
+  NavigableSet<Integer> filter(
+      NavigableSet<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}
diff --git a/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java b/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java
new file mode 100644
index 000000000000..0529bead6ccd
--- /dev/null
+++ b/guava-tests/test/com/google/common/collect/SetsFilterSortedSetTest.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2012 The Guava Authors
+ *
+ * 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.common.collect;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredSortedSetTest;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
+public final class SetsFilterSortedSetTest
+    extends AbstractFilteredSortedSetTest<SortedSet<Integer>> {
+  @Override
+  SortedSet<Integer> createUnfiltered(Iterable<Integer> contents) {
+    final TreeSet<Integer> result = Sets.newTreeSet(contents);
+    // we have to make the result not Navigable
+    return new ForwardingSortedSet<Integer>() {
+      @Override
+      protected SortedSet<Integer> delegate() {
+        return result;
+      }
+    };
+  }
+
+  @Override
+  SortedSet<Integer> filter(SortedSet<Integer> elements, Predicate<? super Integer> predicate) {
+    return Sets.filter(elements, predicate);
+  }
+}