Lib/test/test_future.py

# Test various flavors of legal and illegal future statements

import unittest
from test import support
import os
import re

rx = re.compile(r'\((\S+).py, line (\d+)')

def get_error_location(msg):
    mo = rx.search(str(msg))
    return mo.group(1, 2)

class FutureTest(unittest.TestCase):

    def check_syntax_error(self, err, basename, lineno, offset=0):
        self.assertIn('%s.py, line %d' % (basename, lineno), str(err))
        self.assertEqual(os.path.basename(err.filename), basename + '.py')
        self.assertEqual(err.lineno, lineno)
        self.assertEqual(err.offset, offset)

    def test_future1(self):
        with support.CleanImport('future_test1'):
            from test import future_test1
            self.assertEqual(future_test1.result, 6)

    def test_future2(self):
        with support.CleanImport('future_test2'):
            from test import future_test2
            self.assertEqual(future_test2.result, 6)

    def test_future3(self):
        with support.CleanImport('test_future3'):
            from test import test_future3

    def test_badfuture3(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future3
        self.check_syntax_error(cm.exception, "badsyntax_future3", 3)

    def test_badfuture4(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future4
        self.check_syntax_error(cm.exception, "badsyntax_future4", 3)

    def test_badfuture5(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future5
        self.check_syntax_error(cm.exception, "badsyntax_future5", 4)

    def test_badfuture6(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future6
        self.check_syntax_error(cm.exception, "badsyntax_future6", 3)

    def test_badfuture7(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future7
        self.check_syntax_error(cm.exception, "badsyntax_future7", 3, 53)

    def test_badfuture8(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future8
        self.check_syntax_error(cm.exception, "badsyntax_future8", 3)

    def test_badfuture9(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future9
        self.check_syntax_error(cm.exception, "badsyntax_future9", 3, 0)

    def test_badfuture10(self):
        with self.assertRaises(SyntaxError) as cm:
            from test import badsyntax_future10
        self.check_syntax_error(cm.exception, "badsyntax_future10", 3, 0)

    def test_parserhack(self):
        # test that the parser.c::future_hack function works as expected
        # Note: although this test must pass, it's not testing the original
        #       bug as of 2.6 since the with statement is not optional and
        #       the parser hack disabled. If a new keyword is introduced in
        #       2.6, change this to refer to the new future import.
        try:
            exec("from __future__ import print_function; print 0")
        except SyntaxError:
            pass
        else:
            self.fail("syntax error didn't occur")

        try:
            exec("from __future__ import (print_function); print 0")
        except SyntaxError:
            pass
        else:
            self.fail("syntax error didn't occur")

    def test_multiple_features(self):
        with support.CleanImport("test.test_future5"):
            from test import test_future5

    def test_unicode_literals_exec(self):
        scope = {}
        exec("from __future__ import unicode_literals; x = ''", {}, scope)
        self.assertIsInstance(scope["x"], str)



if __name__ == "__main__":
    unittest.main()