mirror of
https://github.com/python/cpython.git
synced 2025-10-25 10:44:55 +00:00
2c318a1390
and relies much more on meta path finders to abstract out various parts of import. As part of this the semantics for import_module tightened up and now follow __import__ much more closely (biggest thing is that the 'package' argument must now already be imported, else a SystemError is raised).
76 lines
3 KiB
Python
76 lines
3 KiB
Python
"""Test that sys.modules is used properly by import."""
|
|
from .. import util
|
|
from . import util as import_util
|
|
import sys
|
|
from types import MethodType
|
|
import unittest
|
|
|
|
|
|
class UseCache(unittest.TestCase):
|
|
|
|
"""When it comes to sys.modules, import prefers it over anything else.
|
|
|
|
Once a name has been resolved, sys.modules is checked to see if it contains
|
|
the module desired. If so, then it is returned [use cache]. If it is not
|
|
found, then the proper steps are taken to perform the import, but
|
|
sys.modules is still used to return the imported module (e.g., not what a
|
|
loader returns) [from cache on return]. This also applies to imports of
|
|
things contained within a package and thus get assigned as an attribute
|
|
[from cache to attribute] or pulled in thanks to a fromlist import
|
|
[from cache for fromlist].
|
|
|
|
"""
|
|
def test_using_cache(self):
|
|
# [use cache]
|
|
module_to_use = "some module found!"
|
|
sys.modules['some_module'] = module_to_use
|
|
module = import_util.import_('some_module')
|
|
self.assertEqual(id(module_to_use), id(module))
|
|
|
|
def create_mock(self, *names, return_=None):
|
|
mock = util.mock_modules(*names)
|
|
original_load = mock.load_module
|
|
def load_module(self, fullname):
|
|
original_load(fullname)
|
|
return return_
|
|
mock.load_module = MethodType(load_module, mock)
|
|
return mock
|
|
|
|
# __import__ inconsistent between loaders and built-in import when it comes
|
|
# to when to use the module in sys.modules and when not to.
|
|
@import_util.importlib_only
|
|
def test_using_cache_after_loader(self):
|
|
# [from cache on return]
|
|
with self.create_mock('module') as mock:
|
|
with util.import_state(meta_path=[mock]):
|
|
module = import_util.import_('module')
|
|
self.assertEquals(id(module), id(sys.modules['module']))
|
|
|
|
# See test_using_cache_after_loader() for reasoning.
|
|
@import_util.importlib_only
|
|
def test_using_cache_for_assigning_to_attribute(self):
|
|
# [from cache to attribute]
|
|
with self.create_mock('pkg.__init__', 'pkg.module') as importer:
|
|
with util.import_state(meta_path=[importer]):
|
|
module = import_util.import_('pkg.module')
|
|
self.assert_(hasattr(module, 'module'))
|
|
self.assert_(id(module.module), id(sys.modules['pkg.module']))
|
|
|
|
# See test_using_cache_after_loader() for reasoning.
|
|
@import_util.importlib_only
|
|
def test_using_cache_for_fromlist(self):
|
|
# [from cache for fromlist]
|
|
with self.create_mock('pkg.__init__', 'pkg.module') as importer:
|
|
with util.import_state(meta_path=[importer]):
|
|
module = import_util.import_('pkg', fromlist=['module'])
|
|
self.assert_(hasattr(module, 'module'))
|
|
self.assertEquals(id(module.module),
|
|
id(sys.modules['pkg.module']))
|
|
|
|
|
|
def test_main():
|
|
from test.support import run_unittest
|
|
run_unittest(UseCache)
|
|
|
|
if __name__ == '__main__':
|
|
test_main()
|