--- /dev/null
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test unary addition in various contexts.
+
+// Test value context.
+assertEquals(1, +'1');
+assertEquals(1, +1);
+assertEquals(1.12, +1.12);
+assertEquals(NaN, +undefined);
+assertEquals(NaN, +{});
+
+// Test effect context.
+assertEquals(1, eval("+'1'; 1"));
+assertEquals(1, eval("+1; 1"));
+assertEquals(1, eval("+1.12; 1"));
+assertEquals(1, eval("+undefined; 1"));
+assertEquals(1, eval("+{}; 1"));
+
+// Test test context.
+assertEquals(1, (+'1') ? 1 : 2);
+assertEquals(1, (+1) ? 1 : 2);
+assertEquals(1, (+'0') ? 2 : 1);
+assertEquals(1, (+0) ? 2 : 1);
+assertEquals(1, (+1.12) ? 1 : 2);
+assertEquals(1, (+undefined) ? 2 : 1);
+assertEquals(1, (+{}) ? 2 : 1);
+
+// Test value/test context.
+assertEquals(1, +'1' || 2);
+assertEquals(1, +1 || 2);
+assertEquals(1.12, +1.12 || 2);
+assertEquals(2, +undefined || 2);
+assertEquals(2, +{} || 2);
+
+// Test test/value context.
+assertEquals(2, +'1' && 2);
+assertEquals(2, +1 && 2);
+assertEquals(0, +'0' && 2);
+assertEquals(0, +0 && 2);
+assertEquals(2, +1.12 && 2);
+assertEquals(NaN, +undefined && 2);
+assertEquals(NaN, +{} && 2);