diff --git a/test/harness/decimalToHexString.js b/test/harness/decimalToHexString.js
new file mode 100644
index 0000000000000000000000000000000000000000..5a114a97beba2fb6b6e6000b764a50e03e25d2f9
--- /dev/null
+++ b/test/harness/decimalToHexString.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2017 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: >
+    Including decimalToHexString.js will expose two functions:
+
+      decimalToHexString
+      decimalToPercentHexString
+
+includes: [decimalToHexString.js]
+---*/
+
+assert.sameValue(decimalToHexString(-1), "FFFFFFFF");
+assert.sameValue(decimalToHexString(0.5), "0000");
+assert.sameValue(decimalToHexString(1), "0001");
+assert.sameValue(decimalToHexString(100), "0064");
+assert.sameValue(decimalToHexString(65535), "FFFF");
+assert.sameValue(decimalToHexString(65536), "10000");
+
+assert.sameValue(decimalToPercentHexString(-1), "%FF");
+assert.sameValue(decimalToPercentHexString(0.5), "%00");
+assert.sameValue(decimalToPercentHexString(1), "%01");
+assert.sameValue(decimalToPercentHexString(100), "%64");
+assert.sameValue(decimalToPercentHexString(65535), "%FF");
+assert.sameValue(decimalToPercentHexString(65536), "%00");