diff -r aac6b313ef5f Lib/test/json_tests/test_tool.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/test/json_tests/test_tool.py	Sun Nov 25 17:03:12 2012 +0200
@@ -0,0 +1,53 @@
+import os
+import textwrap
+import unittest
+from test import support
+from test.script_helper import assert_python_ok
+from test.support import TESTFN
+
+class TestTool(unittest.TestCase):
+    data = """
+
+        [["blorpie"],[ "whoops" ] , [
+                                 ],\t"d-shtaeou",\r"d-nthiouh",
+        "i-vhbjkhnth", {"nifty":87}, {"morefield" :\tfalse,"field"
+            :"yes"}  ]
+           """
+
+    expect = textwrap.dedent("""\
+    [
+        [
+            "blorpie"
+        ],
+        [
+            "whoops"
+        ],
+        [],
+        "d-shtaeou",
+        "d-nthiouh",
+        "i-vhbjkhnth",
+        {
+            "nifty": 87
+        },
+        {
+            "field": "yes",
+            "morefield": false
+        }
+    ]
+    """)
+
+    def test_tool(self):
+        infile = support.TESTFN
+        with open(infile, "w") as fp:
+            self.addCleanup(os.remove, infile)
+            fp.write(self.data)
+        rc, out, err = assert_python_ok('-m', 'json.tool', infile)
+        self.assertEqual(out, self.expect.encode())
+        self.assertEqual(err, b'')
+        outfile = support.TESTFN + '.out'
+        rc, out, err = assert_python_ok('-m', 'json.tool', infile, outfile)
+        self.addCleanup(os.remove, outfile)
+        with open(outfile, "r") as fp:
+            self.assertEqual(fp.read(), self.expect)
+        self.assertEqual(out, b'')
+        self.assertEqual(err, b'')