file_object, expected_file_line)

self.assertEqual(expect, file_object.getvalue())

def test_formatwarning_override(self):

# bpo-35178: Test that a custom formatwarning function gets the 'line'

# argument as a positional argument, and not only as a keyword argument

def myformatwarning(message, category, filename, lineno, text):

return f'm={message}:c={category}:f={filename}:l={lineno}:t={text}'

file_name = os.path.splitext(warning_tests.__file__)[0] + '.py'

line_num = 3

file_line = linecache.getline(file_name, line_num).strip()

message = 'msg'

category = Warning

file_object = StringIO()

expected = f'm={message}:c={category}:f={file_name}:l={line_num}' + \

f':t={file_line}'

with support.swap_attr(self.module, 'formatwarning', myformatwarning):

self.module.showwarning(message, category, file_name, line_num,

file_object, file_line)

self.assertEqual(file_object.getvalue(), expected)

class CWarningsDisplayTests(WarningsDisplayTests, unittest.TestCase):

module = c_warnings

if fw is not _formatwarning_orig:

# warnings.formatwarning() was replaced

return fw(msg.message, msg.category,

msg.filename, msg.lineno, line=msg.line)

msg.filename, msg.lineno, msg.line)

return _formatwarnmsg_impl(msg)

def filterwarnings(action, message="", category=Warning, module="", lineno=0,

Ensure custom :func:`warnings.formatwarning` function can receive `line` as

positional argument. Based on patch by Tashrif Billah.