diff -r 000000000000 -r 6474c204b198 js/src/gdb/tests/test-jsval.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/gdb/tests/test-jsval.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+# Basic unit tests for jsval pretty-printer.
+
+assert_subprinter_registered('SpiderMonkey', 'JS::Value')
+
+run_fragment('jsval.simple')
+
+assert_pretty('fortytwo', '$jsval(42)')
+assert_pretty('negone', '$jsval(-1)')
+assert_pretty('undefined', 'JSVAL_VOID')
+assert_pretty('null', 'JSVAL_NULL')
+assert_pretty('js_true', 'JSVAL_TRUE')
+assert_pretty('js_false', 'JSVAL_FALSE')
+assert_pretty('elements_hole', '$jsmagic(JS_ELEMENTS_HOLE)')
+assert_pretty('empty_string', '$jsval("")')
+assert_pretty('friendly_string', '$jsval("Hello!")')
+assert_pretty('global', '$jsval((JSObject *)  [object global] delegate)')
+assert_pretty('onehundredthirtysevenonehundredtwentyeighths', '$jsval(1.0703125)')