diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_5/JSON/shell.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_5/JSON/shell.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,112 @@
+gTestsubsuite='JSON';
+
+function testJSON(str, expectSyntaxError)
+{
+  // Leading and trailing whitespace never affect parsing, so test the string
+  // multiple times with and without whitespace around it as it's easy and can
+  // potentially detect bugs.
+
+  // Try the provided string
+  try
+  {
+    JSON.parse(str);
+    reportCompare(false, expectSyntaxError,
+                  "string <" + str + "> " +
+                  "should" + (expectSyntaxError ? "n't" : "") + " " +
+                  "have parsed as JSON");
+  }
+  catch (e)
+  {
+    if (!(e instanceof SyntaxError))
+    {
+      reportCompare(true, false,
+                    "parsing string <" + str + "> threw a non-SyntaxError " +
+                    "exception: " + e);
+    }
+    else
+    {
+      reportCompare(true, expectSyntaxError,
+                    "string <" + str + "> " +
+                    "should" + (expectSyntaxError ? "n't" : "") + " " +
+                    "have parsed as JSON, exception: " + e);
+    }
+  }
+
+  // Now try the provided string with trailing whitespace
+  try
+  {
+    JSON.parse(str + " ");
+    reportCompare(false, expectSyntaxError,
+                  "string <" + str + " > " +
+                  "should" + (expectSyntaxError ? "n't" : "") + " " +
+                  "have parsed as JSON");
+  }
+  catch (e)
+  {
+    if (!(e instanceof SyntaxError))
+    {
+      reportCompare(true, false,
+                    "parsing string <" + str + " > threw a non-SyntaxError " +
+                    "exception: " + e);
+    }
+    else
+    {
+      reportCompare(true, expectSyntaxError,
+                    "string <" + str + " > " +
+                    "should" + (expectSyntaxError ? "n't" : "") + " " +
+                    "have parsed as JSON, exception: " + e);
+    }
+  }
+
+  // Now try the provided string with leading whitespace
+  try
+  {
+    JSON.parse(" " + str);
+    reportCompare(false, expectSyntaxError,
+                  "string < " + str + "> " +
+                  "should" + (expectSyntaxError ? "n't" : "") + " " +
+                  "have parsed as JSON");
+  }
+  catch (e)
+  {
+    if (!(e instanceof SyntaxError))
+    {
+      reportCompare(true, false,
+                    "parsing string < " + str + "> threw a non-SyntaxError " +
+                    "exception: " + e);
+    }
+    else
+    {
+      reportCompare(true, expectSyntaxError,
+                    "string < " + str + "> " +
+                    "should" + (expectSyntaxError ? "n't" : "") + " " +
+                    "have parsed as JSON, exception: " + e);
+    }
+  }
+
+  // Now try the provided string with whitespace surrounding it
+  try
+  {
+    JSON.parse(" " + str + " ");
+    reportCompare(false, expectSyntaxError,
+                  "string < " + str + " > " +
+                  "should" + (expectSyntaxError ? "n't" : "") + " " +
+                  "have parsed as JSON");
+  }
+  catch (e)
+  {
+    if (!(e instanceof SyntaxError))
+    {
+      reportCompare(true, false,
+                    "parsing string < " + str + " > threw a non-SyntaxError " +
+                    "exception: " + e);
+    }
+    else
+    {
+      reportCompare(true, expectSyntaxError,
+                    "string < " + str + " > " +
+                    "should" + (expectSyntaxError ? "n't" : "") + " " +
+                    "have parsed as JSON, exception: " + e);
+    }
+  }
+}