from unittest import TestCase import json import textwrap from io import StringIO class TestIndent(TestCase): def test_indent(self): h = [['blorpie'], ['whoops'], [], 'd-shtaeou', 'd-nthiouh', 'i-vhbjkhnth', {'nifty': 87}, {'field': 'yes', 'morefield': False} ] expect = textwrap.dedent("""\ [ \t[ \t\t"blorpie" \t], \t[ \t\t"whoops" \t], \t[], \t"d-shtaeou", \t"d-nthiouh", \t"i-vhbjkhnth", \t{ \t\t"nifty": 87 \t}, \t{ \t\t"field": "yes", \t\t"morefield": false \t} ]""") d1 = json.dumps(h) d2 = json.dumps(h, indent=2, sort_keys=True, separators=(',', ': ')) d3 = json.dumps(h, indent='\t', sort_keys=True, separators=(',', ': ')) h1 = json.loads(d1) h2 = json.loads(d2) h3 = json.loads(d3) self.assertEqual(h1, h) self.assertEqual(h2, h) self.assertEqual(h3, h) self.assertEqual(d2, expect.expandtabs(2)) self.assertEqual(d3, expect) def test_indent0(self): h = {3: 1} def check(indent, expected): d1 = json.dumps(h, indent=indent) self.assertEqual(d1, expected) sio = StringIO() json.dump(h, sio, indent=indent) self.assertEqual(sio.getvalue(), expected) # indent=0 should emit newlines check(0, '{\n"3": 1\n}') # indent=None is more compact check(None, '{"3": 1}')