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1import os
2import sys
3import shutil
4import string
5import random
6import tempfile
7import unittest
8
9from importlib.util import cache_from_source
10from test.support import create_empty_file
11
12class TestImport(unittest.TestCase):
13
14    def __init__(self, *args, **kw):
15        self.package_name = 'PACKAGE_'
16        while self.package_name in sys.modules:
17            self.package_name += random.choice(string.ascii_letters)
18        self.module_name = self.package_name + '.foo'
19        unittest.TestCase.__init__(self, *args, **kw)
20
21    def remove_modules(self):
22        for module_name in (self.package_name, self.module_name):
23            if module_name in sys.modules:
24                del sys.modules[module_name]
25
26    def setUp(self):
27        self.test_dir = tempfile.mkdtemp()
28        sys.path.append(self.test_dir)
29        self.package_dir = os.path.join(self.test_dir,
30                                        self.package_name)
31        os.mkdir(self.package_dir)
32        create_empty_file(os.path.join(self.package_dir, '__init__.py'))
33        self.module_path = os.path.join(self.package_dir, 'foo.py')
34
35    def tearDown(self):
36        shutil.rmtree(self.test_dir)
37        self.assertNotEqual(sys.path.count(self.test_dir), 0)
38        sys.path.remove(self.test_dir)
39        self.remove_modules()
40
41    def rewrite_file(self, contents):
42        compiled_path = cache_from_source(self.module_path)
43        if os.path.exists(compiled_path):
44            os.remove(compiled_path)
45        with open(self.module_path, 'w') as f:
46            f.write(contents)
47
48    def test_package_import__semantics(self):
49
50        # Generate a couple of broken modules to try importing.
51
52        # ...try loading the module when there's a SyntaxError
53        self.rewrite_file('for')
54        try: __import__(self.module_name)
55        except SyntaxError: pass
56        else: raise RuntimeError('Failed to induce SyntaxError') # self.fail()?
57        self.assertNotIn(self.module_name, sys.modules)
58        self.assertFalse(hasattr(sys.modules[self.package_name], 'foo'))
59
60        # ...make up a variable name that isn't bound in __builtins__
61        var = 'a'
62        while var in dir(__builtins__):
63            var += random.choice(string.ascii_letters)
64
65        # ...make a module that just contains that
66        self.rewrite_file(var)
67
68        try: __import__(self.module_name)
69        except NameError: pass
70        else: raise RuntimeError('Failed to induce NameError.')
71
72        # ...now  change  the module  so  that  the NameError  doesn't
73        # happen
74        self.rewrite_file('%s = 1' % var)
75        module = __import__(self.module_name).foo
76        self.assertEqual(getattr(module, var), 1)
77
78
79if __name__ == "__main__":
80    unittest.main()
81