diff --git a/src/test/java/com/samskivert/util/FoldsTest.java b/src/test/java/com/samskivert/util/FoldsTest.java
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+++ b/src/test/java/com/samskivert/util/FoldsTest.java
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+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001-2010 Michael Bayne, et al.
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.util;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+import org.junit.*;
+import static org.junit.Assert.*;
+
+/**
+ * Tests the {@link Folds} class.
+ */
+public class FoldsTest
+{
+    public static List<Integer> INTS = Arrays.asList(5, 4, 3, 6, 1);
+    public static List<Integer> EMPTY_INTS = Collections.<Integer>emptyList();
+
+    public static Folds.R<Integer> INT_MAX = new Folds.R<Integer>() {
+        public Integer apply (Integer zero, Integer elem) {
+            return Math.max(zero, elem);
+        }
+    };
+
+    @Test public void testFold () {
+        assertTrue(6 == Folds.foldLeft(INT_MAX, 0, INTS));
+    }
+
+    @Test public void testReduce () {
+        assertTrue(6 == Folds.reduceLeft(INT_MAX, INTS));
+    }
+
+    @Test(expected=NoSuchElementException.class)
+    public void testEmptyReduce () {
+        Folds.reduceLeft(INT_MAX, EMPTY_INTS);
+    }
+
+    @Test public void testPromotingFold ()
+    {
+        assertTrue(6L + Integer.MAX_VALUE == Folds.foldLeft(new Folds.F<Long,Integer>() {
+            public Long apply (Long zero, Integer elem) {
+                return zero + elem;
+            }
+        }, 0L, Arrays.asList(Integer.MAX_VALUE, 1, 2, 3)));
+    }
+
+    @Test public void testIntSum () {
+        assertEquals(19, Folds.sum(0, INTS));
+    }
+    @Test public void testEmptyIntSum () {
+        assertEquals(0, Folds.sum(0, EMPTY_INTS));
+    }
+
+    public static List<Long> LONGS = Arrays.asList(5L, 4L, 3L, 6L, 1L);
+    public static List<Long> EMPTY_LONGS = Collections.<Long>emptyList();
+
+    @Test public void testLongSum () {
+        assertTrue(19L == Folds.sum(0, LONGS));
+    }
+    @Test public void testEmptyLongSum () {
+        assertTrue(0L == Folds.sum(0, EMPTY_LONGS));
+    }
+}