Add --indent / --no-indent arguments to json.tool

From #201 which is being split into
two pull requests.

See http://bugs.python.org/issue29636

Author: dhimmel

Lib/json/tool.py

@@ -27,6 +27,12 @@ def main():
     parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'),
                         default=sys.stdout,
                         help='write the output of infile to outfile')
+    group = parser.add_mutually_exclusive_group()
+    group.add_argument('--indent', default=4, type=int,
+                       help='Indent level (number of spaces) for '
+                       'pretty-printing. Defaults to 4.')
+    group.add_argument('--no-indent', action='store_const', dest='indent',
+                       const=None, help='Use compact mode.')
     parser.add_argument('--sort-keys', action='store_true',
                         help='sort the output of dictionaries by key')
     options = parser.parse_args()
@@ -39,7 +45,10 @@ def main():
             raise SystemExit(e)
 
     with options.outfile as outfile:
-        json.dump(obj, outfile, sort_keys=options.sort_keys, indent=4)
+        json.dump(obj, outfile,
+                  indent=options.indent,
+                  sort_keys=options.sort_keys,
+                  )
         outfile.write('\n')
 
 

Lib/test/test_json/test_tool.py

@@ -105,3 +105,26 @@ def test_sort_keys_flag(self):
         self.assertEqual(out.splitlines(),
                          self.expect_without_sort_keys.encode().splitlines())
         self.assertEqual(err, b'')
+
+    def test_indent(self):
+        json_stdin = b'[1, 2]'
+        expect = textwrap.dedent('''\
+        [
+          1,
+          2
+        ]
+        ''').encode()
+        args = sys.executable, '-m', 'json.tool', '--indent', '2'
+        with Popen(args, stdin=PIPE, stdout=PIPE, stderr=PIPE) as proc:
+            json_stdout, err = proc.communicate(json_stdin)
+        self.assertEqual(expect.splitlines(), json_stdout.splitlines())
+        self.assertEqual(err, b'')
+
+    def test_no_indent(self):
+        json_stdin = b'[1,\n2]'
+        expect = b'[1, 2]'
+        args = sys.executable, '-m', 'json.tool', '--no-indent'
+        with Popen(args, stdin=PIPE, stdout=PIPE, stderr=PIPE) as proc:
+            json_stdout, err = proc.communicate(json_stdin)
+        self.assertEqual(expect.splitlines(), json_stdout.splitlines())
+        self.assertEqual(err, b'')